Year	Number
1993	28.35656
1994	24.7943
1995	27.67532
1996	23.11992
1997	25.31455
1998	28.38006
1999	29.27835
2000	29.6779
2001	29.5433
2002	27.31257
2003	27.13294
2004	26.7773
2005	25.24396
2006	24.56104
2007	23.48558
2008	22.82661
2009	21.79856
2010	21.35845
2011	21.5332
2012	21.60403
2013	31.09964
2014	32.24587
2015	31.88265
2016	29.87002
2017	29.03824
2018	28.81802