That's an interesting way to look at it.
It was in or around year 1990 that Watchtower started taking greater and more specific measures to have elders give special treatment to reports of child molestation. During the early to late 1990s this likely resulted in a surge of reports of child molestation. To reduce the probability of skewing values I decided to ignore all reports except for the last 10 years. For statistical purposes, this gave any initial number surge a good 15-years of opportunity to subside.
Of those reports I ignored 1) all cases without a clear date (year) of reporting and 2) all cases reported as "Not a JW member".
To me this provides a pretty clear idea of the magnitude of reported cases Watchtower has received worldwide over the past 10 years, and is also a pretty good indicator of what the problem has looked like for a long time (decades!) before that.