The percentages are quite quite small.  

Liberals (and trial lawyer$$) inflate the numbers because it seems to give them power to remake the Church into  the image of something other than God, especially Church teaching when it comes to morality, mainly sex. 

The devil targets sexuality because of its unique and quick ability to corrode the integrality of a person's functions...their will, their intellect/conscience, their body, their passions or appetites. 

The devil is always working against the "unity" of things, of persons, families, the Church, even our understanding of God.

If you look at most formal "heresies" they generally involve a division of something meant to be a unity (the nature of Christ, etc.).