why would I get a negative number on a query time?

[n8w]

For some reason .. I [b]somtimes[/b] get a negative number when I track how long a query takes

most of the time I get a number like:0.064271
but sometimes I get a negative number:[b]-0.765811[/b]

Here is my code
[code]  # execute SQL statement
$start ="";
$querytime="";
$start = microtime(TRUE);
    $retid = mysql_query($sql) or die(mysql_error());
$querytime = microtime(TRUE) - $start;[/code]

You can see it if you go to http://www.illustrationmundo.com/illustrators.php?feature=c and look at the bottom left corner .. hit refresh and the times will change

[AndyB]

http://php.net/microtime - see the comment and example by "php at washboardabs dot net"