Year	Number of
1990	1572.08
1991	1574.84
1992	1567.65
1993	1557.55
1994	1551.01
1995	1566.42
1996	1509.33
1997	1485.61
1998	1450.35
1999	1414.88
2000	1401.75
2001	1383.12
2002	1360.37
2003	1363
2004	1362.89
2005	1365.43
2006	1363.28
2007	1352.4
2008	1353.8
2009	1363.63
2010	1375.43
2011	1380.88
2012	1390.12
2013	1400.08
2014	1417.13
2015	1437.59
2016	1460.66