Year	Number of
1990	103.46
1991	110.43
1992	120.14
1993	131.9
1994	143.96
1995	156.13
1996	161.38
1997	165.51
1998	168.72
1999	172.41
2000	177.95
2001	183.12
2002	190.44
2003	198.77
2004	207.26
2005	216.48
2006	225.36
2007	232.72
2008	240.92
2009	250
2010	261.37
2011	270.25
2012	281.58
2013	293.88
2014	306.84
2015	320.08
2016	336.06