*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 19700070310
1970000000
1971000000
1972000011
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000000
1985000011
1986000000
1987000000
1988000011
1989001001
1990101002
1991001012
1992001001
1993000022
1994404008
1995101002
1996000000
1997001001
1998100001
1999000000
2000000000
2001000000
2002000000
2003000000
2004000000
2005004015
2006400015
2007114006
2008001023
2009101002
20108080218
2011002013
2012103004
2013100001
2014000000
2015100001
2016000000
2017000000
Total2414001681