Are "These Guys" getting better or just smarter?

I just noticed an interesting trend among the Tour Winners that I have been analyzing this year.  With one exception (Tiger @ Torrey Pines) they are hitting more Greens-in-Regulation than the winners from the same events last year.  Of all the old school stats, I have always held this one in high regard.  It represents two positives:  First, the long game has been good enough to get there; and second, it is a birdie opportunity.  I estimate that, on average, each missed GIR on Tour carries a cost of .75 strokes (-30% birdie chance + 44% bogey chance = 74% rounded to 75%). 

I decided to compare the entire field in each of the first five events (graph above) and sure enough EVERYONE is hitting more greens.  But why?

Driving the ball better?  I don't think so.  

   Accuracy is about the same:  56.2% vs. 56.6% for 2012 vs. 2013 respectively. 

   Distance is actually down a bit this year:  289 vs 292 at this point in 2012.

Proximity to Hole is better:   The Tour average YTD is almost two feet closer:  35' 5 vs. 37' 3' (2012).  Remember, even shots missing the green are included in this number so it is not pure putting distance.

Could the answer be improved equipment - the combination of slightly improved irons and balls?  I apologize that I do not have the answer but I will keep watching to see if the trend continues.

One last point of interest.  The scoring is also lower for the field this year vs. last year at the same point:  69.8 vs. 70.5 = .7 strokes lower.  My .75 average cost of a missed GIR comes very close to that number.  Difference in GIR's:  13.3 - 12.5 = .8 x .75 = .6   Close enough!  

Perhaps it is as simple as a growing awareness of the value of the GIR?   SMARTER!