*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000101
1983000000
1984100001
1985000000
1986000000
1987000000
1988000000
1989000000
1990000000
1991000000
1992100001
1993000101
1994000000
1995000000
1996000000
1997000000
1998000000
1999100203
2000000101
2001000000
2002000000
2003000000
2004000000
2005000112
2006000000
2007000101
2008000000
2009000000
2010000000
2011001001
2012000202
2013000000
2014000000
2015000101
2016000101
2017000000
2018000000
Total30111116