PREPARE FOR A SHOCK!
http://www.vgchartz.com/weekly.php?date=40118&console=PSP&maker=&boxartz=1#
MEGA LOL!
Looks like 3D GTA's are way more popular, I found GTA:CTW more fun than the 3D PSP GTA's though!
or is there some other reason? low marketing perhaps?
All hail the KING, Andrespetmonkey