Year	Number of
1990	153.05
1991	164.83
1992	180.61
1993	199.68
1994	219.38
1995	237.3
1996	248.84
1997	257.53
1998	264.8
1999	274.46
2000	286.23
2001	300.47
2002	316.38
2003	334.55
2004	353.37
2005	371.52
2006	387.87
2007	402.85
2008	418.1
2009	433.68
2010	451.77
2011	470.18
2012	491.78
2013	516.44
2014	543.25
2015	570.93
2016	599.43