Year	Number
1977	1.9777732160318229
1978	0.8906611057565794
1979	3.144951496323189
1980	0.8591964319749934
1981	1.0753180919587069
1982	2.011998055366724
1987	1.1920644091634134
1988	1.7786685704087097
1989	2.2401093269559276
1990	2.1809414116572334
1991	1.6988500696937219
1992	2.4379590570652256
1993	0.5652107407179532
1994	1.2231256069815541
1995	1.1505260235514525
1996	1.4925559198085225
1997	2.4280216214347345
1998	2.269016324467177
1999	2.7291997051044072
2000	2.536186157262413
2001	2.046934374881091
2002	2.440965021104009
2003	2.5948077695494915
2004	2.995399013366056
2005	2.840410111516524
2006	2.736125279794639
2007	2.8139998651028866
2008	2.462914497660405
2009	4.047034348833857
2010	3.924051244842338
2011	3.3304948863474384
2012	2.9917406579460533
2013	3.080469019051971
2014	3.5043713185969745
2015	3.774106672294804
2016	3.6879300641242385
2017	3.9656593217471254
2018	3.6196633389662973
2019	4.2238278169991545
2020	5.666731407828458
2021	5.247090513115132
2022	4.612532849377536
2023	5.5664929259455205