Asked "do you believe in the faith you follow through choice?" I would expect most respondents would answer "yes", yet this is clearly not the case and is largely true only for people who have converted from one faith to another.
A child growing up in Belfast with Protestant parents, Protestant grand-parents and Protestant great-grand-parents is going to be Protestant. A child growing up in Italy is 90% certain to be Catholic, a child born and raised in N.E. Thailand is 97% certain to be Buddhist etc etc.
Where does the choice come in?
Surely for anyone who doesn't question belief in God, the God they follow is down not to choice but to geography - does this not make a mockery of belief?