It's not even one year, it's just one
serve. If your intent is to show this is part of a deliberate effort to slow down the court, this is problematic for a number of reasons:
1.
They are not the same serve: even if the serves are hit at the same initial speed, different spin rates or types of spin (eg: more topspin vs flatter) would result in a different bounce height and resulting speed at the baseline
2.
Small sample size: It's
one serve. The sample size is so small that it's not statistically significant at all. All kinds of things can happen when dealing with just one serve. Maybe it hit a bad patch of grass. Maybe the balls were fresher in one serve vs the other.
3.
Ignores weather conditions: grass as a living surface is affected the most by the weather. Notoriously, rain prior to and during the tournament can make the surface play faster. Even if the conditions were truly slower, this could have happened just because of the weather rather than deliberate human intervention
But more important of all is, this contradicts the official stance from Wimbledon that there have been no changes to the surface since 2001.
Of course
@TMF will continue to ignore all these problems and hold on to a throwaway graphic as if it were gospel