Year Percent 1950 4.56258 1955 4.62125 1960 4.54441 1965 4.40535 1970 4.23356 1975 4.08356 1980 4.11472 1985 3.93897 1990 4.24929 1995 4.24766 2000 4.17768 2005 4.08199 2010 3.731 2015 3.61845 2020 3.55635 2025 3.62954 2030 3.90906 2035 4.58782 2040 5.74321 2045 7.24671 2050 8.77928 2055 10.2631 2060 11.62086 2065 13.0068 2070 14.73509 2075 16.79087 2080 18.57796 2085 20.13186 2090 21.57177 2095 22.99845 2100 24.40475