I don't know, it seems like most people don't really understand what it means. A fertility rate of 1.6 means that the kids' generation will only be 80% as big as that of the parents, and that of the grandkids about 64%. In Europe with average fertility rate 1.46 (assuming it doesn't keep dropping even further) the grandkids generation will be about 50% the size of that of the grandparents. Not sure that people really understand these numbers.