Year	Number
1970	1.2158558040229697
1971	3.3581430728914676
1972	1.8048433129921857
1973	1.7273105827948687
1974	1.6034992599984417
1975	1.1852663583953231
1976	0.9550997573173422
1977	3.21013532972325
1978	2.376178366600087
1979	2.325055110043321
1980	2.0089482053441747
1981	1.4115580876315075
1982	1.3033934751302199
1983	1.255715832295385
1984	0.9863624530797108
1985	1.1944467340670741
1986	1.4699545280077655
1987	2.3571512751734547
1988	1.9472444195790093
1989	1.4358813083671977
1990	1.2656414397670686
1991	1.4933540090761337
1992	1.3381269307179289
1993	1.4462537182027528
1994	1.468218493514334
1995	1.2748553872007704
1996	1.123251916655558
1997	0.8482407990853814
1998	0.8497293155221741
1999	0.90959988381713
2000	0.9350571757772336
2001	0.8764044492695587
2002	1.007930322808847
2003	0.9245702466754663
2004	0.8371462977636974
2005	0.6865891429428351
2006	0.5974841340874913
2007	0.6147306702563126
2008	0.5307529791180639
2009	0.9653252645912923
2010	1.135838362109756
2011	1.1166261470104666
2012	1.2118114474122739
2013	1.1982010935814211
2014	1.2098242201601423
2015	1.568857750568472
2016	1.495937334027526
2017	1.5890582343185857
2018	1.6216006570414474
2019	1.6847354480675483
2020	2.1173285286736423
2021	1.9248403774540122
2022	1.4591249191157512
2023	1.3112204279135853