Year	Number of
1990	172.29
1991	176
1992	182.63
1993	187.17
1994	196.12
1995	207.16
1996	216.13
1997	219.97
1998	226.06
1999	232.07
2000	241.04
2001	248.32
2002	255.46
2003	262.64
2004	272.51
2005	281.24
2006	291.54
2007	301.82
2008	315.55
2009	334.22
2010	350.63
2011	366.46
2012	380.39
2013	393.32
2014	405.77
2015	420.54
2016	435.29