*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 19707005012
1970000000
1971200002
1972100001
1973100001
1974100001
1975100001
1976300003
1977100001
1978200002
1979100001
1980100001
1981400004
1982200002
1983100102
1984300003
1985300003
1986400105
1987200103
1988200002
1989100001
1990600006
1991100203
1992300104
1993200002
1994000000
1995100607
1996100809
1997100203
1998400307
1999400004
2000200406
2001500207
2002000404
2003000101
2004010102
2005100102
2006200103
2007000202
2008200204
2009300306
2010000101
2011100102
2012000000
2013000808
2014000000
2015000000
2016000000
2017000101
2018000000
Total8210620145