Year	Number
1960	9.05207475370319
1961	12.503727440912256
1962	8.791202749843137
1963	12.972389312350433
1964	9.131783277633842
1965	8.352989892663645
1966	7.105630305658238
1967	6.495488144563292
1968	7.896532444337219
1969	12.094964968920914
1970	13.74374482949084
1971	9.331176873155858
1972	7.140630130672437
1973	2.8565167005483603
1974	3.153366387987954
1975	3.051154602095621
1976	7.1264127757664735
1977	5.481650293914506
1978	7.659884528462161
1979	4.465078462841834
1980	7.3045851362449
1981	10.416663076954059
1982	13.556605304842076
1983	27.06103814841238
1984	23.121352521264807
1985	34.931002761978085
1986	19.944810365335485
1987	11.159906307182686
1988	10.19329564084425
1989	11.93143973672007
1990	15.068896873276389
1991	16.452383013536164
1992	17.531790027360262
1993	18.960858271199598
1994	13.036083994085132
1995	14.10965362121228
1996	16.070843118378235
1997	19.99017047573005
1998	21.951225055417066
1999	24.954100600935412
2000	33.26089178073383
2001	40.541601115458334
2002	40.75789444091905
2003	38.157656531694386
2004	35.60458989130744
2005	1.1820827121841
2006	1.3534175583864125
2007	1.4960182359880836
2008	1.9992867993124697
2009	2.109975717095216
2010	2.1425776170729796