Year	Number
1980	104.8118855791
1981	104.6788380516
1982	104.5457905241
1983	104.4127429965
1984	104.279695469
1985	104.1466479415
1986	100.2255401976
1987	96.3044324537
1988	92.3833247099
1989	88.462216966
1990	56.3505555966
1991	55.2487249612
1992	54.1468943258
1993	53.0450636903
1994	51.9432330549
1995	50.8414024195
1996	49.7395717841
1997	48.6377411486
1998	47.5359105132
1999	46.4340798778
2000	45.3300317836
2001	43.1177470619
2002	48.7005691478
2003	48.1286126099
2004	47.5566560721
2005	46.9846995343
2006	46.4127429965
2007	45.8407864587
2008	47.4905758001
2009	45.2383768202
2010	44.0535146722
2011	47.1949146278
2012	42.2396333801
2013	40.4168822529
2014	39.7368615567
2015	41.6098750832
2016	42.0504102299
2017	41.8212728213
2018	40.0990464927
2019	40.0768719048
2020	37.5194027644