year to year? No it doesnt.
over 4 years? (the age disparity between couples upon which this discussion is based)also not.
So basically no family size has nothing to do with the discussion at hand. Sure if 60 year olds where marrying 30 year olds there would be a huge problem. But when 24 year olds marry 20 year olds, if there hasnt been a problem when 30 years ago when the 24 & 20 year olds came from smaller familes, there shouldnt be a problem now. (although again, the same problem would appear bigger now, but youd have to assert that unless something else changed, 30 years ago 10% of girls remained single like you claim today)