Year % of total population 1960 2.85702545264127 1961 2.82924502581167 1962 2.80659195567983 1963 2.7885435634668 1964 2.77451874345341 1965 2.76254294926626 1966 2.75265717146173 1967 2.74520000530282 1968 2.73954172267037 1969 2.73527164370139 1970 2.73242860245145 1971 2.73096214480187 1972 2.73043726362116 1973 2.73225944588263 1974 2.73643819171682 1975 2.74262359838365 1976 2.75172013872088 1977 2.76450269874714 1978 2.7811750847793 1979 2.80085797874678 1980 2.82261040707632 1981 2.84509892595362 1982 2.86791374464249 1983 2.89090477219723 1984 2.9147792559243 1985 2.93981248960043 1986 2.96615893180698 1987 2.99390586159311 1988 3.02312368970831 1989 3.0539831461568 1990 3.08493212016109 1991 3.11517257641722 1992 3.14410402590704 1993 3.17085179053654 1994 3.19561696436289 1995 3.21887853952199 1996 3.24030091291013 1997 3.25883826268871 1998 3.27315912770967 1999 3.28244358968529 2000 3.2870938012805 2001 3.28992364379771 2002 3.29238446767662 2003 3.29326147174796 2004 3.2908091279578 2005 3.28423663190377 2006 3.27416181625304 2007 3.26287421623334 2008 3.25279465580903 2009 3.24394485834945 2010 3.2368042081635 2011 3.23066462253454 2012 3.21972397928541 2013 3.199708757977 2014 3.16486233391785 2015 3.14506703227923 2016 3.15095089729545 2017 3.15765626301929 2018 3.16409874369089 2019 3.17237317439776 2020 3.17310898192517 2021 3.15750927905422 2022 3.13908758083138 2023 3.13561835805932