Year	Number of
1990	93.44
1991	97.51
1992	101.99
1993	106.93
1994	111.65
1995	116.75
1996	120.68
1997	126.88
1998	132.88
1999	139.16
2000	146.12
2001	150.6
2002	155.63
2003	160.63
2004	165.52
2005	170
2006	173.92
2007	182.11
2008	187.58
2009	192.71
2010	197.65
2011	205.59
2012	211.78
2013	217.85
2014	224.73
2015	232.64
2016	240.94