*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000257
1970000000
1971000000
1972000011
1973000033
1974000134
1975000022
1976000000
1977000000
1978000011
1979000000
1980000011
1981000101
1982000112
1983000101
1984000011
1985000000
1986000000
1987000000
1988000101
1989000000
1990000000
1991000000
1992000000
1993000000
1994000101
1995000000
1996000101
1997000101
1998000000
1999000000
2000000000
2001000011
2002000033
2003000000
2004000000
2005000000
2006000000
2007000000
2008000000
2009000000
2010000000
2011000011
2012000112
2013000033
2014000011
2015000000
2016000000
2017000000
2018000000
Total000112839