You just need to check his influence in the team during that period.
He did influenced some important games in that time frame.
1. Real Madrid 2011-12 (away, 2-1, Copa) - two amazing passes from Cesc, one for Alexis, who hit the post, and one for Iniesta, who also hit the post. Could have had 2 assists easily.
2. Leverkusen 2011-12 (away, 3-1, CL) - made the assist that got us the lead in Germany 2-1, probably the goal that decided the tie, because the germans managed to make 1-1 and hit the post minutes after.
3. Leverkusen 2011-12 (home, 7-1, CL) - assist again, for Messi, (3-0 goal) with an excellent 40m pass.
4. Milan 2011-12 (home, 3-1, CL) - played a great pass to Messi in the beginning of the game, should've been 1-0 there.
5. Chelsea 2011-12 (away, 0-1, CL) - played a couple of superb passes, one of which ended with a shot that hit the post from Alexis. if Alexis scored there, there would have been a different tie.
6. Chelsea 2011-12 (home, 2-2, CL) - played some amazing passes again, got us a very important penalty, missed by Messi.
7. Malaga 2012-13 (away, 4-2, Copa) - great first touch and assist for Iniesta for 3-2. It was the 75th min. and the tie was dead even, 4-4 aggregate. Very important goal.
8. PSG 2012-13 (away, 2-2, CL) - made the backheel pass that split PSG's defence and set Alexis one vs one with Sirigu. It resulted in the penalty and the goal that made us favourites for the reurn leg.
9. Real Madrid 2012-13 (away, 1-1, Copa) - scored on Bernabeu, when the score was 0-0. Varane equilised late in the game.
10. Manchester City 2013-14 (home, 2-0) - made the asssist to Messi's goal for 1-0. Not the prettiest of assits, but an assist nonetheless.
11. Real Madrid 2013-14 (away, 4-3) - superb pass for Messi, who missed the 2-0 goal.
These are just the most important games where Cesc had significant contributions with excellent passes, assists or goals. All in the 2nd part of the three seasons he played for us. But, yea, Cesc dissappeared after january.