Year	Number of
1990	103.94
1991	109.6
1992	116.4
1993	126.18
1994	134.47
1995	141.94
1996	149.27
1997	153.14
1998	155.27
1999	154.21
2000	154.16
2001	154.59
2002	155.41
2003	157.73
2004	159.49
2005	163.62
2006	167.1
2007	166.92
2008	170.59
2009	173.49
2010	175.15
2011	176.4
2012	177.48
2013	183.84
2014	189.3
2015	195.23
2016	201.95