Year	Number
1974	57.10635
1981	68.77743
1982	68.41566
1993	53.79068
1994	54.85228
1999	56.68684
2000	43.39267
2001	43.35746
2003	31.97703
2008	27.96517
2009	24.21892
2010	27.16736
2011	27.90775
2012	26.1669
2015	23.22706