Year % of total population 1960 23.526299990820583 1961 23.92976297742478 1962 24.33297770411632 1963 24.751352380264674 1964 25.188730372447797 1965 25.617283555544194 1966 26.073295885209504 1967 26.558254742317622 1968 27.074510357734347 1969 27.61791619357541 1970 28.17435947777308 1971 28.61603202720024 1972 29.024537776740683 1973 29.416334389256964 1974 29.78400184086674 1975 30.153980576745457 1976 30.546315829431563 1977 30.94686118394834 1978 31.359599286344423 1979 31.794531279091785 1980 32.25610521251683 1981 32.448277048688496 1982 32.58408306958954 1983 32.70263564419684 1984 32.8373179839958 1985 32.99149364255509 1986 33.16407665681127 1987 33.35501957328756 1988 33.56365321916858 1989 33.78695781191096 1990 34.00012089750591 1991 34.16398729208794 1992 34.28790085644436 1993 34.40808284631833 1994 34.53960022238285 1995 34.69227338104871 1996 34.86345958987699 1997 35.044595308543556 1998 35.24536263037238 1999 35.46686461698293 2000 35.69337258203018 2001 35.79549655519782 2002 35.895926987323705 2003 35.99989535101874 2004 36.11894366095085 2005 36.25059997476722 2006 36.396193211466574 2007 36.55847887979648 2008 36.737155214779186 2009 36.911647971221335 2010 36.994716968501 2011 37.13016868697991 2012 37.26814099545679 2013 37.42037466240241 2014 37.585169200808394 2015 37.7602144174823 2016 37.91802103876159 2017 38.08905471254363 2018 38.28399856730691 2019 38.40568099674637 2020 38.55903804197224 2021 38.75202759845745 2022 38.946802525839885 2023 39.10865272377008