Year	Number of
1990	115.37
1991	118.38
1992	123.04
1993	127.29
1994	132.03
1995	137.51
1996	143.82
1997	149.64
1998	152.2
1999	152.21
2000	160.04
2001	164.51
2002	166.34
2003	168.6
2004	171.15
2005	172.25
2006	174.54
2007	181.64
2008	188.86
2009	195.46
2010	199.27
2011	203.16
2012	206.46
2013	210.36
2014	214.44
2015	219
2016	223.74