That's an ambitious extrapolation there.
Barbara Anderson's original statisitical data is based over a significant time period - four years - and on a significant pool of people - 132,000.
It would be interesting to compare that against the mean for the general population
OK, looking at just the UK, and again using Barbara Anderson's original statisitical data as the base point - in 4 years, 25 JW ministers were convicted of child molestation charges in the UK - assuming that means publishers, rather than just appointed elders/MSs. That's 25 divided by 4 = 6.25 convictions of child molestion-per-year (actual)
In the UK, over a 15 year period (1997 to 2012) there were 29,837 registered offenders convicted of offences against children aged under 18. (I understand these offences are actually more general and include, for example, violence against children)
29,837 divided by 15 years = 1,989-convicted offenders-a-year
Population of the UK in 2011 was 63,182,000 divided by 1,989 convicted offenders = 1 convicted offender for every 31,766 people in the UK-per-year
Average number of JW publishers in 2011 in the UK was 130,808
If JWs had the same number of convicted offenders as per the annual national average: 130,808 divided by 31,766 = 4.12 convictions-per-year (national average)
Therefore the above figures indicate a 50% higher rate than the national average in the UK (but please check my maths!)
In response to a written question, the then Home Office Minister Jeremy Browne stated that, as at 6 September 2012, there were 29,837 offenders whose details were on the Violent and Sex Offenders Register (ViSOR) Dangerous Persons Database who had convictions against children (aged under 18). These figures only include people who have committed offences since the introduction of the Sex Offenders Act 1997 (on 1 September 1997).
https://www.nspcc.org.uk/preventing-abuse/child-abuse-and-neglect/child-sexual-abuse/sexual-abuse-facts-statistics/