Year Percent 1950 29.01064 1955 28.81156 1960 28.59139 1965 29.04468 1970 29.58768 1975 30.81417 1980 31.06981 1985 33.59322 1990 34.26462 1995 32.81435 2000 30.58632 2005 29.13424 2010 27.61837 2015 26.91441 2020 26.13291 2025 24.86763 2030 23.95651 2035 23.20003 2040 22.62022 2045 22.55454 2050 22.39682 2055 22.3361 2060 22.28447 2065 22.17335 2070 22.01824 2075 21.85969 2080 21.73717 2085 21.63942 2090 21.52109 2095 21.37151 2100 21.19211