Year Percent 1950 14.74004 1955 14.84593 1960 15.52794 1965 15.47489 1970 15.97428 1975 13.17525 1980 11.90562 1985 10.51299 1990 9.67896 1995 8.63031 2000 9.19196 2005 8.04941 2010 7.59915 2015 6.40316 2020 5.4025 2025 5.14957 2030 5.14401 2035 5.18718 2040 5.07572 2045 4.83842 2050 4.59849 2055 4.49015 2060 4.54219 2065 4.64508 2070 4.6874 2075 4.65019 2080 4.58196 2085 4.56126 2090 4.61689 2095 4.70827 2100 4.76689