What are the EF data?

In his recent motu proprio, the pope asserts that many who attend Mass in the Extraordinary Form are opposed to Vatican II. But are they? Bishops were sent a questionnaire about this. How many actually returned the questionnaires? Do the faithful have reason to believe that they have been misunderstood, or perhaps that a stray remark from one of their members mistakenly has been taken as representing the views of their entire community?