Australia's bowling debacle, and left-arm seamers on the rise

Traditionally, Australia haven't cared much for the Twenty20 version of cricket, but the manner in which they exited the tournament was still a shock. Twice they had reasonable scores to defend, and twice they failed quite miserably. Apart from Nathan Hauritz, none of the bowlers seemed to have any semblance of control over the run-scoring.

What will especially disappoint Ricky Ponting is the frequency with which his team gave away boundaries. In the 209 balls they bowled, Australia conceded 31 fours and 11 sixes, which is a boundary every 4.98 deliveries - that's an average of 24 in a 20-over innings. Among all teams in the competition, only Scotland gave away boundaries more generously - one every 3.63 balls.

Compare those figures with South Africa's, who were the most stingy, averaging about two overs per boundary conceded. Ireland were a model of discipline too - even against teams ranked much higher than them, they allowed a boundary only once every 10 balls.

Among the batting teams, Sri Lanka and West Indies were the best of the lot in the group stages. They were the only ones to average more than nine runs per over, and they did that with a flurry of boundaries. The Sri Lankans struck 39 fours, easily the highest of all teams, with Tillakaratne Dilshan alone hitting 21, by far the highest by a single player. They averaged fewer than five balls per boundary, while West Indies were only marginally behind them. Australia didn't do too badly with the bat, striking a four or a six roughly every over - in fact, the 13 sixes they struck was the highest by any team. However, they were let down badly by their bowlers, which eventually led to a swift exit from the tournament.

Overall, though, Australia have done much better than in this tournament, averaging more than six-and-a-half deliveries per boundary conceded, which is better than five teams. New Zealand have been the most profligate, but part of the reason for that is also the small size of their home grounds, where scoring boundaries is much easier than in most other countries. (Click here for the performances of Australian bowlers in this format.)

Meanwhile, those two defeats for Australia have also ensured that their win-loss ratio has dipped below 1 - they've won 11 and lost 12 Twenty20 internationals. Six teams have a better ratio than theirs. However, the ICC World Twenty20 also brought Ireland their first defeat in this format, which suggests we perhaps shouldn't be taking all of these numbers that seriously just yet.

It's well known that left-hand batsmen have become an increasingly common sight over the last few years, but can the same argument be made for left-arm fast bowlers as well? In the 1990s, Wasim Akram and Chaminda Vaas were the two consistently representing that tribe, but they had little support: in that decade, only Akram and Vaas took more than 100 Test wickets, with Allan Mullally (54) and Bruce Reid (51) the only others above the 50-mark.

In the 2000s, though, the group has visibly grown - there are seven who've taken more than 75 Test wickets. Zaheer Khan and Mitchell Johnson are leading the pack today very ably - both can lay claim to being among the best in the world - while several others, like Ryan Sidebottom, RP Singh and Irfan Pathan, have all had their moments, even if they haven't performed consistently in all forms of the game.

As the table below indicates, left-arm fast bowlers are making a much greater contribution in this decade in percentage terms as well. In the 1990s, they accounted for 10.72% of wickets taken by all fast bowlers - which itself was a huge increase from the barren 1980s - but in the 2000s this figure has gone up to 14.26, while left-armers only form 10.46% of the total number of fast/ medium-fast bowlers in this decade.

There isn't much to choose between the averages and strike-rates for left-arm and right-arm fast bowlers, though. In the last two decades, the left-armers have done marginally better than the overall figure for fast bowlers, conceding slightly fewer runs per wicket.

Breaking up the numbers into Tests and ODIs, it's obvious that left-arm fast bowlers have had more success in the limited-overs version recently, with a better average and economy-rate than the corresponding numbers for all fast bowlers. That's due to Nathan Bracken and a few others, for whom ODIs have been far more profitable. (Click here for left-arm fast bowlers in ODIs in the 2000s.)

The left-arm fast bowlers were very successful in the IPL, but in Twenty20 internationals they average slightly higher than all fast bowlers, though their economy-rate is marginally better.