Year Number 1960 134761 1961 137714 1962 139561 1963 141434 1964 143334 1965 145255 1966 147203 1967 149178 1968 151183 1969 153497 1970 156734 1971 160040 1972 163420 1973 166862 1974 170381 1975 173975 1976 177649 1977 181391 1978 185217 1979 189123 1980 193644 1981 198261 1982 202994 1983 207840 1984 212809 1985 217882 1986 223084 1987 228410 1988 233870 1989 239852 1990 247270 1991 254918 1992 262814 1993 270931 1994 279311 1995 287950 1996 296869 1997 306038 1998 315503 1999 325262 2000 335336 2001 344700 2002 351285 2003 357995 2004 364843 2005 371803 2006 378905 2007 386143 2008 393529 2009 401036 2010 408697 2011 416504 2012 424471 2013 432590 2014 440865 2015 449298 2016 457892 2017 466651 2018 475577 2019 484624 2020 493712 2021 502734 2022 511559 2023 520058.99999999994