Year Percent 1950 26.90973 1955 28.5653 1960 30.67999 1965 28.13097 1970 23.48248 1975 24.47687 1980 24.80567 1985 27.34027 1990 28.04055 1995 27.97519 2000 28.44279 2005 29.85863 2010 31.72177 2015 32.48209 2020 32.50636 2025 31.14464 2030 30.12422 2035 30.47068 2040 30.99623 2045 31.59405 2050 31.06294 2055 29.94024 2060 29.2466 2065 29.08755 2070 29.07414 2075 28.73645 2080 27.96873 2085 27.05371 2090 26.31788 2095 25.81693 2100 25.37166