A couple of decades ago, wicketkeepers in Test cricket were judged by how well they kept wicket; their batting skills were useful, but their place in the team didn't depend on it. An average in the mid-20s, or even lower, was acceptable. Rod Marsh played 96 Tests and scored only three hundreds, averaging 26.51; Godfrey Evans averaged 20.49 in 91 matches. India's Syed Kirmani did better, managing 27.04 runs per dismissal, but for Wasim Bari it was only 15.88 in 81 matches, and England's Bob Taylor averaged 16.28 in 57. Most of these players only had average skills with the bat, but they were all outstanding behind the stumps, because of which they enjoyed long careers.

In the last couple of decades, though, the batting skills of wicketkeepers have come into far greater prominence. Adam Gilchrist, Andy Flower, and more recently Matt Prior and MS Dhoni, have gradually changed the job description for wicketkeepers: from a role that required excellence behind the stumps and merely passable skills with the bat, it's now a role which needs more-than-adequate batting skills, to go with clean glovemanship.

As the graphic shows, from an average of 20.60 in the 1950s, the batting average of wicketkeepers has gone up to 31.81 in the 2000s, and 33.74 since the beginning of 2010. In the 1980s, wicketkeepers scored only 14 centuries in 773 innings - an average of one every 55 innings; in the 1990s that rate came down to one every 36 innings, with 30 hundreds in 1086 innings; in the 2000s it reduced further to 23, as 65 hundreds were scored in 1490 innings. (Click here for the full decade-wise stats since the 1920s.)

In terms of batting averages by decades, wicketkeepers have never had it as good as since 2010, averaging 33.74 from the beginning of that year. However, it seems no one has told Pakistan's wicketkeepers that this is supposed to be their best period with the bat: in these last four years, they've averaged a miserable 19.44, which is their second-lowest in any decade; the only decade in which they averaged lower was in the 1970s, when, in 69 innings, they scored 17.98 runs per dismissal. That's also the only decade, apart from the current one, when there was no century scored by a Pakistan wicketkeeper: the highest in the 1970s was Bari's 85 against India in 1978; their highest since 2010 is 88 by Zulqarnain Haider at Edbgaston.

Compared to the poor batting numbers for Pakistan's wicketkeepers, some of the other countries have done remarkably well. South Africa lead the way with five hundreds and a superb average of 45.15, while Bangladesh, thanks to Mushfiqur Rahim, have done very well too. England, India and Sri Lanka are the other teams whose wicketkeepers have averaged more than 35 with the bat.

Team-wise batting stats for wicketkeepers in Tests since Jan 2010
Team Tests Runs Average 100s/ 50s
South Africa 35 2032 45.15 5/ 10
Bangladesh 20 1399 39.97 2/ 8
England 52 2579 38.49 5/ 16
India 43 2231 35.98 3/ 12
Sri Lanka 33 1553 35.29 4/ 6
Australia 47 2513 33.95 4/ 17
New Zealand 33 1661 33.89 4/ 8
West Indies 33 1230 27.33 3/ 5
Zimbabwe 10 424 22.31 0/ 2
Pakistan 36 1050 19.44 0/ 5

Pakistan have been getting very few runs from their wicketkeepers in these last four years, but it wasn't always so. During the five years from 2005 to 2009, the batting average for Pakistan's wicketkeeper - there was only one during that period, Kamran Akmal - was 38.98, twice the average over the last four years. (The problem for Pakistan during that period, though, was the number of runs Akmal gave away by dropping crucial catches.)

Among the regular Test-playing teams, only Australia had a better batting average by their wicketkeepers, and even there the difference was marginal - just one run separated Australia and Pakistan. The two top teams in this aspect over the last four years - South Africa and Bangladesh - were in the bottom half during that period: South Africa averaged 30, and Bangladesh less than 23.

Team-wise batting stats for wicketkeepers in Tests between 2005 and 2009
Team Tests Runs Average 100s/ 50s
Zimbabwe 8 607 43.35 1/ 5
Australia 56 2999 39.98 7/ 12
Pakistan 38 2300 38.98 6/ 11
India 51 2557 36.01 3/ 19
Sri Lanka 45 2229 35.38 4/ 6
England 64 2712 30.13 3/ 19
South Africa 52 2100 30.00 1/ 13
New Zealand 39 1850 29.83 2/ 10
Bangladesh 27 1062 22.59 0/ 4
West Indies 47 1556 21.02 1/ 9

In the recently concluded series against Sri Lanka, Sarfraz Ahmed, Pakistan's wicketkeeper, scored 134 runs in four innings at an average of 33.50, with a highest of 74. Those aren't outstanding stats, but Sarfraz's performances were encouraging simply because they were much better than those of other Pakistan wicketkeepers in the last few series: in the two-match series against South Africa in the UAE, the average was 12.33; on the tour to South Africa it was 13.83 in six innings; against England in the UAE in 2011-12 it was 17.80 in five innings; and against England in England in 2010 it was 14 in eight innings.

Sarfraz himself did much better against Sri Lanka than he had in his previous Test opportunities: in eight Test innings before this series, he'd scored 89 runs at an average of 11.12. Compared to those numbers, what he achieved against Sri Lanka was encouraging, and perhaps not a complete surprise to Pakistan fans given that he has already scored seven first-class centuries, and averages 40.11 in those matches.

However, in the period since 2010, there isn't a single Pakistan wicketkeeper in the list of top ten batting averages (with a 15-innings cut-off). AB de Villiers tops the list with an incredible average of 60.21 in 25 innings, while New Zealand's BJ Watling has been superb too, beefing up their lower order with some solid performances. Matt Prior had two wretched Ashes series recently, but his overall average during this period is still a healthy 40.15, thanks to his consistency from 2010 to the early part of 2013. Mushfiqur Rahim falls just one run short of an average of 40, with ten 50-plus scores in 37 innings.

Pakistan's wicketkeepers during this period have done little of note with the bat. Adnan Akmal has scored the most runs - 591 - but it's taken him 29 innings to make them, at an average of 24.62. Haider's played only two innings, but the others have nothing to recommend themselves.

Top batting averages for wicketkeepers in Tests since Jan 2010 (Qual: 15 inngs)
Player Innings Runs Average 100s/ 50s
AB de Villiers 25 1385 60.21 5/ 5
BJ Watling 17 698 46.53 2/ 5
Matt Prior 76 2530 40.15 5/ 16
Mushfiqur Rahim 37 1399 39.97 2/ 8
Denesh Ramdin 27 816 38.85 3/ 3
MS Dhoni 65 2166 37.34 3/ 12
Matthew Wade 22 623 34.61 2/ 3
Brad Haddin 53 1603 33.39 2/ 12
Prasanna Jayawardene 37 1017 31.78 2/ 3
Mark Boucher 24 647 29.40 0/ 5

Between 2005 and 2009, Pakistan had Kamran Akmal to represent them among the top wicketkeeper-batsmen, in terms of batting at least. His glovework was often questioned, but as a batsman his numbers were up there with those of Prior, Haddin, Dhoni and Gilchrist. He scored six centuries in 65 innings, but since then Pakistan have had none in 59.

However, Sarfraz's batting displays against Sri Lanka were encouraging, and his first-class stats suggest he clearly has some batting skill. Adnan Akmal was the first-choice keeper for the series before he injured his finger in the first Test, but his first-class batting stats aren't as impressive as Sarfraz's: an average of 25.72, with 22 fifty-plus scores in 173 innings. The wicketkeeping skills will obviously be the key aspect, but Pakistan will hope that whichever player they opt for will contribute a little more with bat in hand as well.

Top batting averages for wicketkeepers in Tests between 2005 and 2009 (Qual: 20 inngs)
Player Innings Runs Average 100s/ 50s
Matt Prior 40 1390 42.12 2/ 11
Brad Haddin 38 1404 41.29 2/ 5
MS Dhoni 62 2176 40.29 3/ 16
Adam Gilchrist 44 1574 39.35 5/ 7
Kamran Akmal 65 2300 38.98 6/ 11
Kumar Sangakkara 29 1080 38.57 2/ 4
Prasanna Jayawardene 37 1035 33.38 2/ 2
Brendon McCullum 62 1823 30.38 2/ 10

S Rajesh is stats editor of ESPNcricinfo. Follow him on Twitter