Year	Number of
1990	65.57
1991	70.5
1992	74.8
1993	79.03
1994	82.63
1995	85.42
1996	88.98
1997	95.03
1998	100.43
1999	107.33
2000	115.59
2001	126.45
2002	135.38
2003	145.38
2004	154.23
2005	162.7
2006	171.98
2007	181.2
2008	190.97
2009	201.23
2010	211.84
2011	222.18
2012	234.04
2013	243.02
2014	250.51
2015	256.47
2016	263.34