Year	Number of
1990	372.74
1991	389.66
1992	401.82
1993	432.17
1994	447.22
1995	459.72
1996	440.96
1997	418.87
1998	406.31
1999	408.32
2000	414.31
2001	404.48
2002	419.94
2003	425.7
2004	437.62
2005	439.52
2006	451.65
2007	463.38
2008	466.12
2009	472.88
2010	465.85
2011	469.56
2012	470.54
2013	482.52
2014	493.61
2015	501.85
2016	513.79