Year Percent 1950 6.78483 1955 6.33291 1960 7.90759 1965 7.8187 1970 8.2535 1975 8.51761 1980 7.74337 1985 6.96286 1990 6.35885 1995 6.23167 2000 6.23571 2005 6.24844 2010 5.80788 2015 5.73038 2020 5.99999 2025 5.96409 2030 5.90125 2035 5.68981 2040 5.51989 2045 5.42301 2050 5.46072 2055 5.54175 2060 5.57904 2065 5.55638 2070 5.48316 2075 5.41446 2080 5.3829 2085 5.3842 2090 5.37787 2095 5.34839 2100 5.28771