*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979002002
1980000000
1981000000
1982000000
1983000000
1984000000
1985001001
1986002002
1987003003
1988003003
1989000000
1990001001
1991007007
1992004004
1993001001
1994003003
199500120012
1996008008
1997005005
199800100010
1999007007
200000290029
200100320032
200200250025
200300280028
2004005005
2005009009
2006004004
2007006006
2008009009
2009008008
2010006006
201100120012
2012006006
2013002002
2014000000
2015001001
2016000000
2017000000
Total0025100251