Roughly how many churches were built in each century?

Christians build churches - it's what we do. Are there any estimates of how many physical church buildings Christians have built over the centuries, broken down by century? Suitable proxies: - number of towns and cities that have a church. - number of monasteries (smaller, but maybe people more likely to count them) **I am particularly interested in the period from Emperor Constantine (4th century) through 1000 AD.** Mostly interested in seeing rough growth pattern. If numbers are only for Western Europe (Roman Catholic), please specify. That will also be acceptable.