Year % of cohort 1960 32.248556 1961 32.557873 1962 32.959218 1963 33.257476 1964 33.415269 1965 29.199086 1966 32.931299 1967 32.623874 1968 32.796448 1969 31.86711 1970 32.442998 1971 32.353377 1972 7.128621 1973 22.522854 1974 32.58931 1975 32.656641 1976 32.677323 1977 33.006881 1978 33.167237 1979 34.19174 1980 35.075431 1981 36.41582 1982 37.563151 1983 38.40634 1984 38.46551 1985 37.935908 1986 36.651806 1987 34.948311 1988 26.300745 1989 31.148481 1990 29.722483 1991 28.896529 1992 28.822781 1993 18.113392 1994 28.944385 1995 28.51402 1996 28.829255 1997 30.674388 1998 32.544883 1999 34.357187 2000 33.361443 2001 34.690172 2002 37.760292 2003 39.65226 2004 41.745111 2005 43.268993 2006 44.535857 2007 45.973287 2008 46.854561 2009 48.003109 2010 49.459883 2011 50.426317 2012 51.433847 2013 52.468201 2014 53.331286 2015 52.84796 2016 54.32704 2017 55.468054 2018 55.409225 2019 56.284806 2020 53.673836 2021 53.964584 2022 54.57275