Year	Number of
1990	168.87
1991	166.19
1992	168.27
1993	168.99
1994	169.55
1995	169.34
1996	168.05
1997	166.35
1998	164.65
1999	165.84
2000	165.91
2001	165.98
2002	166.07
2003	166.14
2004	157
2005	148.73
2006	156.76
2007	162.99
2008	168.19
2009	173.93
2010	174.75
2011	178.11
2012	182.7
2013	187.17
2014	192.1
2015	196.6
2016	201.28