I do not have any figures for you, but you need only look at the registration in certain French-language schools, for example. The fact that francophone schools are expanding suggests that, if day care services were available, more children would come and feed into those schools.
You cited your own case. I personally know a lot of people around me, in my community, who put their children in an anglophone day care centre because there is no francophone centre. We are losing a lot of children right now.