Year	Number of
1990	15910.39
1991	16522.05
1992	17166.09
1993	17844.16
1994	18565.79
1995	19345.17
1996	20118.37
1997	20959.54
1998	21869.75
1999	22844.37
2000	23894.35
2001	24590.66
2002	25341.03
2003	26134.54
2004	26976.37
2005	27886.47
2006	28612.85
2007	29412.42
2008	30296.79
2009	31253.48
2010	32305.52
2011	33758.05
2012	35270.01
2013	36833.33
2014	38484.49
2015	40232.22
2016	41951.96