Year Percent 1950 28.94702 1955 26.11213 1960 24.2424 1965 21.99393 1970 22.04229 1975 25.95647 1980 29.2054 1985 33.48894 1990 35.03095 1995 34.48268 2000 30.84933 2005 28.83723 2010 27.20584 2015 25.65947 2020 24.65782 2025 23.64024 2030 23.10374 2035 22.66863 2040 22.50753 2045 22.33742 2050 22.22849 2055 22.10635 2060 22.02928 2065 21.97506 2070 21.9243 2075 21.85475 2080 21.74569 2085 21.61885 2090 21.48964 2095 21.37876 2100 21.28352