Year Percent 1950 25.76752 1955 25.59704 1960 29.2533 1965 33.20549 1970 33.30593 1975 29.72349 1980 31.12982 1985 30.64235 1990 33.9454 1995 38.10478 2000 35.37731 2005 34.60733 2010 31.82352 2015 29.88642 2020 30.49587 2025 30.03519 2030 28.96888 2035 27.58744 2040 26.71907 2045 26.29124 2050 26.31111 2055 26.11633 2060 25.49154 2065 24.69081 2070 24.06425 2075 23.76382 2080 23.66292 2085 23.51005 2090 23.16484 2095 22.71216 2100 22.33993