Here are his inning numbers, and stolen base attempts over the last few years. His CS has definitely gone down, but teams aren't increasing their amounts of stolen base attempts.
2011 687.1 ip, 52 sba, 18 CS
2012 877.0 ip, 66 sba, 32 CS
2013 589.2 ip, 33 sba, 15 CS
2014 603.2 ip, 38 sba, 8 CS