Year	Number of
1990	95.17
1991	99.1
1992	102.35
1993	106.43
1994	111.65
1995	117.58
1996	125.23
1997	132.66
1998	140.1
1999	147.81
2000	155.69
2001	159.19
2002	164.35
2003	168.32
2004	170.26
2005	170.18
2006	170.14
2007	169.13
2008	170.42
2009	172.16
2010	174.04
2011	175.98
2012	178.83
2013	182.5
2014	186.4
2015	190.24
2016	193.48