Junction Guy you offer some astute comments on the "public" face JWs present when they are identifiably commenting on "their" views. This undoubtedly contrasts to the times they participate anonymously and confidentially during these sorts of stratified sampling surveys - which explains why the result is seldom, if ever, 100% of JW respondents voicing the exact same view.
Of course, there are large numbers of JWs who voice as their own opinion whatever the GB spouts.
Each religious group has its hard core believers, and, as it ages, a larger core of middling adherents and an even larger core of nominals. This is happening in the organization the older it gets and the longer the wait for the end. It is the dreary story of organized religion doen through the centuries.