Year	Number of
1990	84.04
1991	85.62
1992	88.19
1993	91.07
1994	93.26
1995	96.5
1996	99.63
1997	102.76
1998	106.26
1999	116.75
2000	130.27
2001	143.71
2002	158.89
2003	176.42
2004	193.94
2005	213.48
2006	224.78
2007	229.86
2008	239.46
2009	249.15
2010	262.1
2011	273.36
2012	286.87
2013	304.21
2014	320.12
2015	332.8
2016	347.14