Year Percent 1950 16.66652 1955 16.56776 1960 15.72995 1965 15.87422 1970 16.12069 1975 16.3166 1980 17.77671 1985 18.50969 1990 19.15168 1995 21.23277 2000 23.64342 2005 27.83701 2010 30.10762 2015 30.96501 2020 28.27293 2025 24.59189 2030 21.76703 2035 18.96838 2040 19.45628 2045 20.97641 2050 22.47031 2055 23.58257 2060 23.48104 2065 22.50763 2070 21.24786 2075 21.73938 2080 21.86248 2085 21.98625 2090 21.76523 2095 21.24022 2100 20.73045