Year	Number of
1990	141.71
1991	145.14
1992	148.47
1993	151.75
1994	155.3
1995	159.02
1996	161.01
1997	163.48
1998	166.13
1999	169.03
2000	170.94
2001	170.95
2002	172.51
2003	173.71
2004	175.21
2005	177.39
2006	179.17
2007	180.57
2008	182.1
2009	184.61
2010	186.98
2011	190.61
2012	194.95
2013	200.08
2014	205.84
2015	210.75
2016	215.58