Ask your pastor how many families actually give to your Church (this can be measured by how many use weekly envelopes, or use a credit card for monthly or weekly donations). He'll know, and I'll bet he will tell you.
Then come back and share it with us. There may some differences here and there, but most suburban parishes are supported by less than a third of those who attend Mass or are registered.
That does not constitute documentation of the numbers you claim, nor does it answer the other questions I asked, nor would two parishes establish any better than one the truth on the whole.