Year Percent 1950 29.10353 1955 29.92703 1960 30.25276 1965 30.37629 1970 29.20698 1975 28.9869 1980 28.46979 1985 28.07823 1990 27.63685 1995 27.76467 2000 27.94077 2005 27.33451 2010 27.34456 2015 28.11625 2020 28.89628 2025 29.49635 2030 29.83939 2035 30.13663 2040 30.38425 2045 30.69825 2050 30.99638 2055 31.12069 2060 31.10577 2065 31.05664 2070 30.98988 2075 30.88519 2080 30.75614 2085 30.60338 2090 30.43703 2095 30.26605 2100 30.08174