Year Percent 1950 27.96884 1955 27.34591 1960 26.79309 1965 26.4787 1970 26.58829 1975 27.24558 1980 28.40349 1985 29.96121 1990 31.41961 1995 32.63782 2000 32.96724 2005 32.62019 2010 31.8664 2015 30.81177 2020 30.10385 2025 29.51548 2030 29.07166 2035 28.82592 2040 28.35922 2045 27.88331 2050 27.32292 2055 26.63377 2060 26.02058 2065 25.44269 2070 24.8625 2075 24.28374 2080 23.73082 2085 23.21936 2090 22.76083 2095 22.36542 2100 22.02637