Year Percent 1950 30.1199 1955 29.89667 1960 29.32976 1965 28.49829 1970 27.78406 1975 27.84576 1980 27.98153 1985 28.42275 1990 29.22553 1995 29.86182 2000 30.40424 2005 30.82014 2010 30.81809 2015 30.84954 2020 31.24928 2025 31.66214 2030 32.14194 2035 32.27011 2040 31.95802 2045 31.58001 2050 31.2408 2055 31.03053 2060 30.8192 2065 30.56188 2070 30.25586 2075 29.94135 2080 29.64429 2085 29.34752 2090 29.04973 2095 28.70906 2100 28.33042