Year	Number
1975	20.471585081544376
1977	10.196512314882693
1978	5.572217279491636
1979	5.498925582160576
1980	6.850598082562053
1981	5.114987290483679
1982	5.203785701690644
1983	4.794680905933175
1984	4.489554235053074
1985	6.553080987262746
1986	7.243017313461206
1987	7.530272793125296
1988	6.297118173472607
1989	5.084092992614789
1990	4.4810490083885215
1991	4.295492979710549
2005	18.595917108274655
2006	22.438353803473458
2007	24.71019722529111
2008	26.167304819609356
2009	27.20153535366232
2010	27.50723332091972
2011	32.99637719117658
2012	31.150287820594944
2013	30.4680908609937
2014	27.34353628050303
2015	25.451240280027978
2016	27.826896200762796
2017	25.549631893757446
2018	23.327717850763
2019	21.29906819991743
2020	25.921760113227965
2021	20.525237567695626
2022	16.47099486595878