Year Number 1960 231625 1961 235892 1962 239414 1963 242089 1964 243818 1965 244652 1966 244865 1967 245532 1968 247200 1969 248500 1970 249183 1971 250304 1972 251488 1973 252080 1974 252430 1975 252430 1976 251873 1977 251400 1978 251287 1979 251474 1980 252507 1981 254263 1982 256573 1983 259878 1984 263635 1985 266994 1986 270483 1987 274697 1988 278997 1989 281422 1990 281509 1991 280194 1992 275605 1993 268591 1994 261525 1995 253999 1996 245952 1997 237154 1998 227379 1999 217346 2000 207473 2001 197076 2002 186994 2003 178474 2004 170908 2005 164083 2006 158684 2007 154829 2008 152158 2009 149652 2010 146943 2011 145130 2012 144750 2013 145045 2014 145274 2015 145354 2016 145519 2017 145733 2018 145489 2019 144993 2020 144011 2021 142270 2022 141068 2023 140001