Year Percent 1950 6.75667 1955 5.91545 1960 6.84864 1965 7.28414 1970 7.35302 1975 6.78185 1980 5.68045 1985 5.30231 1990 5.46723 1995 5.87751 2000 6.25206 2005 6.09323 2010 5.64726 2015 5.21962 2020 5.30457 2025 5.5679 2030 5.51449 2035 5.41507 2040 5.3315 2045 5.24793 2050 5.21532 2055 5.25655 2060 5.30904 2065 5.30657 2070 5.26253 2075 5.20016 2080 5.14289 2085 5.10123 2090 5.07465 2095 5.03938 2100 4.98864