You get 2.1 because they only want to show 2 significant digits, but it's important to show that the number is greater than 2.0. From individual families' pers

You get 2.1 because they only want to show 2 significant digits, but it's important to show that the number is greater than 2.0. From individual families' perspectives, you can only have a whole number of kids anyway, so 2.1 vs. 2.04 isn't a meaningful difference.