Year Percent 1950 27.26913 1955 22.81683 1960 24.2251 1965 23.6129 1970 27.75431 1975 29.44552 1980 30.0598 1985 33.83773 1990 30.78371 1995 29.07343 2000 29.02393 2005 28.18427 2010 29.31383 2015 29.73879 2020 28.21494 2025 25.62793 2030 23.21483 2035 21.51193 2040 20.9658 2045 21.46255 2050 21.66945 2055 21.30139 2060 20.69238 2065 20.11893 2070 19.9475 2075 20.25349 2080 20.74541 2085 21.04636 2090 20.97943 2095 20.67251 2100 20.38249