Year	Number of
1990	1485.82
1991	1485.7
1992	1486.13
1993	1474.18
1994	1449.91
1995	1423.34
1996	1415.4
1997	1372.28
1998	1318.73
1999	1294.69
2000	1269.56
2001	1263.59
2002	1237.12
2003	1200.78
2004	1193.23
2005	1187.76
2006	1174.86
2007	1157.65
2008	1134.13
2009	1103.61
2010	1067.03
2011	1043.96
2012	1026.77
2013	1004.88
2014	996.99
2015	996.29
2016	990.39