Year	Number of
1990	1617.56
1991	1603.33
1992	1605.42
1993	1594.55
1994	1523.44
1995	1488.42
1996	1497.12
1997	1463.21
1998	1440.51
1999	1427.21
2000	1403.54
2001	1389.15
2002	1394.04
2003	1394.75
2004	1363.61
2005	1316.96
2006	1315.2
2007	1311.13
2008	1319.32
2009	1330.53
2010	1333.72
2011	1321.59
2012	1332.17
2013	1343.97
2014	1345.65
2015	1374.14
2016	1422.29