Year Percent 1950 13.66769 1955 12.0998 1960 15.16027 1965 14.51014 1970 14.47971 1975 15.10866 1980 12.68382 1985 11.42449 1990 11.30935 1995 12.34825 2000 10.36154 2005 9.27582 2010 8.38364 2015 7.80858 2020 7.60215 2025 7.18004 2030 6.67922 2035 6.34673 2040 6.05289 2045 5.8026 2050 5.6098 2055 5.44133 2060 5.28139 2065 5.13074 2070 5.00994 2075 4.92003 2080 4.85401 2085 4.79885 2090 4.75069 2095 4.70127 2100 4.66423