Year Percent 1950 5.40735 1955 4.72035 1960 4.3158 1965 3.4767 1970 2.92474 1975 3.11168 1980 2.39884 1985 1.7926 1990 2.27812 1995 2.49194 2000 2.97467 2005 2.46027 2010 1.83208 2015 2.34278 2020 3.6169 2025 5.67004 2030 8.61131 2035 11.42576 2040 13.59438 2045 15.60004 2050 18.24914 2055 21.51472 2060 24.17911 2065 26.64592 2070 28.60088 2075 30.10193 2080 31.24282 2085 32.10584 2090 32.79337 2095 33.2846 2100 33.75796