Once again the techsuits showed what an advantage they provided for sprint freestylers. The average Top 25 time of 1999-2007 was 49.13, whereas in 2008 and 2009 the average times were 47.99 (drop of 1.14 seconds) and 47.78 (drop of 1.35 seconds) respectively.
The fastest time of the period 1999-2007 was Pieter van den Hoogenband's Sydney Olympic winning time of 47.84. In 2009 this would have only been good enough for 15th in the world rankings.
Of the average Top 5 times the year 2000 stands out as being particularly fast for its time; the average Top 5 time for that year was quicker than all other textile years apart from 2007. Another year that stands out is 2006 where the fastest time in the world (48.57) was the slowest of all the world's fastest times over the period 99-09, however the 25th fastest time (49.32) in 2006 was faster than all years with the exception of 2007-2009.
The average Top 25 swims were at their fastest (excluding the techsuit era) between 2004 and 2007. So when trying to predict 2010 standards this must be taken into account, however it is also fair to assume most of the times from 2004-2007 would have been set in textile shoulder suits or full legs which complicates things slightly as they are now also banned.
I predict the average Top 5 time in the world this year will be 48.35 and the average Top 25 time will be 48.91.
* I've gone back as far as 1999 and used that as the start date for my comparisons; had I gone back any further there would have been a big drop off in times. From all 275 Top 25 times in the world between 1999 and 2009 there was only one swim over 50 seconds. However in 1998 there were only 15 sub-50 second swims.