Year	Number
1960	4.91627259038378
1961	4.997106646417998
1962	5.638007379981419
1963	6.254709782180387
1964	4.970176796066223
1965	5.387714971564678
1966	5.792025383060058
1967	5.9869631172311175
1968	3.662214126695001
1969	4.641100178890877
1970	5.678754067875407
1971	4.421843775128155
1972	6.458337851171436
1973	8.932946209026177
1974	1.3383760505061697
1975	0.8520218758032085
1976	0.7547394446174686
1977	0.6616085777487132
1978	0.6755993495647232
1979	0.7334723334537342
1980	0.636709612459656
1981	0.6792592579198486
1982	0.9922884966817972
1983	1.555569206241772
1984	2.5310259186862614
1985	3.0070495656873293
1986	4.606830762864403
1987	11.034604529646227
1988	14.90442804842166
1989	7.979307993464207
1990	4.433359421145106
1991	6.516576516199737
1992	11.40794540876582
1993	8.70487005915111
1994	5.609323467878216
1995	5.717042749086417
1996	4.690660269542353
1997	3.9100017932826447
1998	4.016916581162199
1999	3.479009438466344
2000	2.666389935080961
2001	2.236492178218513
2002	2.125522466179449
2003	1.7520425328527989
2004	1.617798781879202
2005	1.3116208923818065
2006	1.1842315553342737
2007	1.2913783757949864
2008	1.0766815050812681
2009	1.3483101929314931
2010	1.2987959279342223
2011	1.1978794699846596
2012	1.5366797617380057
2013	1.4574007706166412
2014	1.390672181162257
2015	1.6361861810397855
2016	1.6862725051848688
2017	1.8697833361659806
2018	2.0928733467396694
2019	2.3597438197647267
2020	2.520049057299376
2021	2.5871151433709305
2022	2.655352096695021
2023	2.9419479545671012