Year % of total population 1960 31.075852742505 1961 31.516833925875 1962 31.7664645296199 1963 31.7764283921791 1964 31.5507736644015 1965 31.2029845069099 1966 30.8052398197201 1967 30.3464838443217 1968 29.829191102391 1969 29.2440355250325 1970 28.6112880618957 1971 27.963113498647 1972 27.2945831171839 1973 26.5985052574698 1974 25.9001978890143 1975 25.2147517382334 1976 24.5539685728599 1977 23.9543456530488 1978 23.459020628235 1979 23.1139715229681 1980 22.9141907968794 1981 22.813971946581 1982 22.7898313606278 1983 22.8395933906158 1984 22.9231513836273 1985 22.9882166669578 1986 23.0556516727163 1987 23.112874806158 1988 23.1568261611771 1989 23.178661886613 1990 23.1333290182456 1991 23.0098321161423 1992 22.8090072387523 1993 22.5222719925087 1994 22.1390134758171 1995 21.6754004322053 1996 21.144796333699 1997 20.537301327137 1998 19.864728496333 1999 19.1852028121463 2000 18.5167673225202 2001 17.815457845019 2002 17.1119407126763 2003 16.454506005338 2004 15.8605209899785 2005 15.3809253054026 2006 15.028426940992 2007 14.7996699771402 2008 14.7071065627852 2009 14.7620227394601 2010 14.9249385521774 2011 15.1479736517475 2012 15.4280041705227 2013 15.7326645847987 2014 16.022717548785 2015 16.2867455022669 2016 16.5228607834069 2017 16.6971075856346 2018 16.7788682123858 2019 16.8126098372633 2020 16.8397311511557 2021 16.8403350640924 2022 16.7758482748921 2023 16.6341378264053