Shaatra: No one claims that there didn’t exist some large families years ago. The question is the numbers. I don’t even think there’s a debate that families of 10 kids (in the askenazai non chasidishe community) are much more commonplace now than 25 years ago.
This not so gradual population explosion has been going on for quite some time, which is why in the last 10 yrs the shidduch crisis has reached such proportions. For a more exact mathematical breakdown i leave to the mathematicians.