"time_start","time_end","fleet","obs"
1973,1974,1,103
1977,1978,1,1
1978,1979,1,409
1979,1980,1,103
1980,1981,1,13
1981,1982,1,525
1982,1983,1,666
1983,1984,1,599
1984,1985,1,163
1986,1987,1,258
1987,1988,1,50
1988,1989,1,100
1989,1990,1,200
1990,1991,1,324
1991,1992,1,14
1992,1993,1,475
1993,1994,1,514
1994,1995,1,59
1995,1996,1,1624
1996,1997,1,11
1997,1998,1,12
1999,2000,1,228
2000,2001,1,1909
2001,2002,1,4545
2002,2003,1,4662
2003,2004,1,288
2004,2005,1,722
2005,2006,1,626
2006,2007,1,40
2007,2008,1,36
2008,2009,1,20
2009,2010,1,22
2010,2011,1,25
2011,2012,1,14
2012,2013,1,36
2013,2014,1,1
2014,2015,1,1
2001.75,2001.75,2,133
2002.75,2002.75,2,144
2003.75,2003.75,2,141
2004.75,2004.75,2,143
2005.75,2005.75,2,111
2006.75,2006.75,2,98
2007.75,2007.75,2,79
2008.75,2008.75,2,82
2009.75,2009.75,2,80
2010.75,2010.75,2,97
2011.75,2011.75,2,58
2012.75,2012.75,2,94
2013.75,2013.75,2,136
2014.75,2014.75,2,76
2009.75,2009.75,3,73
2010.75,2010.75,3,90
2011.75,2011.75,3,50
2012.75,2012.75,3,83
2013.75,2013.75,3,121
2014.75,2014.75,3,60
1967.5,1967.5,4,1967
1968.5,1968.5,4,1968
1969.5,1969.5,4,1969
1970.5,1970.5,4,1970
1971.5,1971.5,4,1971
1972.5,1972.5,4,1972
1973.5,1973.5,4,1973
1974.5,1974.5,4,1974
1975.5,1975.5,4,1975
1976.5,1976.5,4,1976
1977.5,1977.5,4,1977
1978.5,1978.5,4,1978
1979.5,1979.5,4,1979
1980.5,1980.5,4,1980
1981.5,1981.5,4,1981
1982.5,1982.5,4,1982
1983.5,1983.5,4,1983
1984.5,1984.5,4,1984
1985.5,1985.5,4,1985
1986.5,1986.5,4,1986
1987.5,1987.5,4,1987
1988.5,1988.5,4,1988
1989.5,1989.5,4,1989
1990.5,1990.5,4,1990
1991.5,1991.5,4,1991
1992.5,1992.5,4,1992
1993.5,1993.5,4,1993
1994.5,1994.5,4,1994
1995.5,1995.5,4,1995
1996.5,1996.5,4,1996
1997.5,1997.5,4,1997
1998.5,1998.5,4,1998
1999.5,1999.5,4,1999
2000.5,2000.5,4,2000
2001.5,2001.5,4,2001
2002.5,2002.5,4,2002
2003.5,2003.5,4,2003
2004.5,2004.5,4,2004
2005.5,2005.5,4,2005
2006.5,2006.5,4,2006
2007.5,2007.5,4,2007
2008.5,2008.5,4,2008
2009.5,2009.5,4,2009
2010.5,2010.5,4,2010
2011.5,2011.5,4,2011
2012.5,2012.5,4,2012
2013.5,2013.5,4,2013
2014.5,2014.5,4,2014