Year	Number of
1990	68.02
1991	71.34
1992	74.88
1993	78.71
1994	82.82
1995	87.1
1996	91.49
1997	95.91
1998	100.47
1999	105.3
2000	110.71
2001	118.76
2002	126.8
2003	134.79
2004	143.41
2005	152.62
2006	156.22
2007	161.03
2008	166.45
2009	172.33
2010	178.15
2011	183.35
2012	185.84
2013	188.34
2014	190.88
2015	193.42
2016	196.34