year,days
1968,0
1969,0
1970,0
1971,0
1972,0
1973,0
1974,0
1975,0
1976,0
1977,0
1978,0
1979,0
1980,0
1981,0
1982,0
1983,0
1984,0
1985,0
1986,0
1987,0
1988,0
1989,0
1990,0
1991,0
1992,0
1993,0
1994,0
1995,0
1996,0
1997,0
1998,0
1999,0
2000,0
2001,2
2002,0
2003,0
2004,0
2005,0
2006,2
2007,3
2008,0
2009,0
2010,0
2011,5
2012,1
2013,0
2014,1
2015,0
2016,7