Year Number 1960 -10332 1961 -10165 1962 -10843 1963 -11980 1964 -13252 1965 -13693 1966 -17072 1967 -16944 1968 -18058 1969 -18341 1970 -17521 1971 -22180 1972 -19647 1973 -19183 1974 -22508 1975 -26632 1976 -34088 1977 -28926 1978 -31602 1979 -32438 1980 -30239 1981 -34216 1982 -34232 1983 -34214 1984 -47454 1985 -63524 1986 -82188 1987 -91198 1988 -88203 1989 -75987 1990 -68856 1991 -77380 1992 -70975 1993 -68995 1994 -63686 1995 -67932 1996 -68134 1997 -56107 1998 -30323 1999 -21740 2000 -17423 2001 -12530 2002 -8926 2003 -11780 2004 -10805 2005 -17436 2006 -18275 2007 -19966 2008 -24538 2009 -34428 2010 -34523 2011 -43216 2012 -140747 2013 -41013 2014 -50149 2015 -48947 2016 -30294 2017 -33995 2018 -40761 2019 -44428 2020 -14978 2021 -22236 2022 -39998 2023 -39998