Year	Number of
1990	1083.16
1991	1093.49
1992	1104.53
1993	1110.09
1994	1109.75
1995	1107.94
1996	1092.32
1997	1079.91
1998	1067.22
1999	1054.29
2000	1040.47
2001	1053.38
2002	1067.21
2003	1077.06
2004	1087.11
2005	1096.52
2006	1096.39
2007	1098.42
2008	1100.22
2009	1105.37
2010	1113.2
2011	1126.38
2012	1142.65
2013	1158.48
2014	1186.23
2015	1216.97
2016	1250.89