Year	Number
1981	21300
1982	35800
1983	40200
1984	45900
1985	55500
1986	65000
1987	65000
1988	61700
1989	58000
1990	58000
1991	67300
1992	68200
1993	70800
1994	74000
1995	77700
1996	77700
1997	69300
1998	70100
1999	68200
2000	62070
2001	72001
2002	63361
2003	67163
2004	25700
2005	26985
2006	26175
2007	27746
2008	28356
2009	26371
2010	39865
2011	36533.603996772
2012	33606.0392244309
2013	52572
2014	46404
2015	40047
2016	40928
2017	24019
2018	23206.966273393
2019	21930.5831283564
2020	64
2021	2105