Year	Number
1970	500330
1971	500850
1972	506370
1974	519978
1975	522671
1978	543477
1979	553498
1980	547186
1981	527412
1982	580701
1983	552430
1997	518553
1999	358112
2000	314831
2001	338243
2002	280614
2004	194875
2005	164815
2006	131840
2007	108802
2008	110679
2009	46051
2010	59498
2011	112895
2012	182449
2013	237111
2014	280541
2015	286107
2016	298432