Year Percent 1950 5.47453 1955 4.97899 1960 4.64477 1965 4.37369 1970 4.20955 1975 4.0641 1980 3.75021 1985 3.42744 1990 3.31572 1995 4.48682 2000 4.13951 2005 4.01569 2010 4.1223 2015 4.21278 2020 4.36018 2025 4.48162 2030 4.65658 2035 5.13162 2040 6.1537 2045 7.47588 2050 9.14064 2055 10.96854 2060 12.37716 2065 13.67044 2070 15.11149 2075 16.79088 2080 18.48798 2085 20.09534 2090 21.58826 2095 22.99673 2100 24.32057