*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976001001
1977001001
1978001001
1979001001
1980000000
1981003003
1982000000
1983000000
1984000000
1985003003
1986004004
1987004004
1988005005
1989001001
1990005005
1991007007
1992005005
199300100010
199400100010
199500260026
1996007007
1997009009
199800130013
1999004004
200000180018
200100110011
200200110011
200300160016
200400140014
200500160016
200600260026
200701190020
200800180018
200900290029
201000280028
201100290029
2012006006
2013005005
2014004004
2015005005
2016001001
2017000000
Total0137600377