Statistics for Valve Video games

Click here to take the quiz!

Hint	Answer	% Correct
1998	half life	96%
2004	half life 2	93%
2007	portal	81%
2011	portal 2	80%
2000	counter strike	73%
2012	counter strike global offensive	69%
2007	Team Fortress 2	62%
2004	counter strike source	52%
2006	half life 2 episode 1	49%
2007	half life 2 episode 2	48%
2008	left 4 dead	48%
2013	dota 2	46%
1999	team fortress classic	44%
2009	left 4 dead 2	43%
2001	half life blue shift	40%
1999	half life opposing force	39%
2003	day of defeat	31%
2004	counter strike condition zero	30%
2000	ricochet	28%
2005	half life 2 lost coast	20%
2005	day of defeat source	19%
2000	deathmatch classic	18%
2010	alien swarn	1%
2004	half lfe 2 deathmatch	0%