Year % of total population 1960 4.72665719704525 1961 4.78263146970288 1962 4.98542323356209 1963 5.23179764699077 1964 5.56906715937582 1965 5.96879801135436 1966 6.41053899711002 1967 6.86336220477596 1968 7.29779890097846 1969 7.71294050986026 1970 8.10839346198916 1971 8.47896870866155 1972 8.80781211612638 1973 9.10323702221202 1974 9.38568589192938 1975 9.64732100302239 1976 9.87198214271512 1977 10.040495552311 1978 10.1270604348588 1979 10.100819297542 1980 9.96891478858842 1981 9.76589468479238 1982 9.52144915708128 1983 9.30130722074304 1984 9.17823348167047 1985 9.1903831228985 1986 9.32768618820667 1987 9.53925336664526 1988 9.79754244789106 1989 10.0991404104124 1990 10.4385167451985 1991 10.8000917325736 1992 11.1559555946455 1993 11.5032717440877 1994 11.881967655761 1995 12.2966205349064 1996 12.7227230908922 1997 13.1761396917259 1998 13.6801036778383 1999 14.199168076312 2000 14.6818811592457 2001 15.1487595628757 2002 15.5840986423981 2003 15.9673585790513 2004 16.322378331648 2005 16.6341950600081 2006 16.9146281847308 2007 17.1643288742944 2008 17.3636963513464 2009 17.5269634911238 2010 17.6937418312086 2011 17.9005588368384 2012 18.1491051097041 2013 18.4587009182566 2014 18.8473626583386 2015 19.2660518736894 2016 19.5924205769216 2017 19.8936955450054 2018 20.2273582700034 2019 20.541428178724 2020 20.7446461876994 2021 20.7201311100935 2022 20.5577047720407 2023 20.4763580302994