Year	Number
1980	8500
1981	9200
1982	10000
1983	9600
1984	10700
1985	10900
1986	10700
1987	11100
1988	11100
1989	11100
1990	11100
1991	11100
1992	11100
1993	3800
1994	4000
1995	10400
1996	10800
1997	10800
1998	11000
1999	12500
2000	11481
2001	12496
2002	13011
2003	9745
2004	11512
2005	12318
2006	13883
2007	13640
2008	13649
2009	13529
2010	7388
2011	7048.95461126849
2012	6659.69835873915
2013	11352
2014	11532
2015	13107
2016	13711
2017	14365
2018	14365
2019	11094
2020	6680.904
2021	5488.635