Year	Number
1960	-23329
1961	-24796
1962	-26156
1963	-26497
1964	-26414
1965	-25486
1966	-27388
1967	-26540
1968	-27554
1969	-28496
1970	-28920
1971	-34623
1972	-33785
1973	-34553
1974	-30690
1975	-30577
1976	-25856
1977	-18974
1978	-19322
1979	-18613
1980	-15379
1981	-17838
1982	-15907
1983	-11651
1984	-12476
1985	-16650
1986	-25107
1987	-29139
1988	-30131
1989	-31911
1990	-33043
1991	-50568
1992	-45114
1993	-43888
1994	-37638
1995	-39033
1996	-44413
1997	-37277
1998	-5376
1999	-1926
2000	3880
2001	10651
2002	16076
2003	15362
2004	17573
2005	9794
2006	-4220
2007	-28226
2008	-40782
2009	-40215
2010	-42128
2011	-33455
2012	-20961
2013	-33275
2014	-18009
2015	-19754
2016	-7603
2017	-14801
2018	-23971
2019	-25277
2020	-5665
2021	-13097
2022	-24998
2023	-24998