Year	Number of
1990	1323.24
1991	1343.35
1992	1358.37
1993	1369.87
1994	1378.45
1995	1382.75
1996	1369.66
1997	1364.06
1998	1367.01
1999	1359.84
2000	1351.56
2001	1351.32
2002	1350.04
2003	1349.23
2004	1333.78
2005	1329.25
2006	1330.29
2007	1333.9
2008	1344.04
2009	1349.83
2010	1352.16
2011	1353.93
2012	1365.01
2013	1389.91
2014	1420.34
2015	1465.08
2016	1513