I am programming on a PHP application since mid last year, and the code is becoming more complicated by the day. I would like to use namespaces, but with PHP 5.2 still being widely used, is it reasonable to switch to PHP >= 5.3 ?

According to the usage stats found here: http://w3techs.com/technologies/details/pl-php/5/all I would exclude about 33% of my customers. Then again, those stats are about servers, not about my customers specifically. (Most hosting companies offer 5.3 or higher these days right?)

Any opinions?