Year,Spring_kg_tow,Fall_kg_tow
1963,,17.95
1964,,22.799
1965,,12.005
1966,,12.916
1967,,9.225
1968,18.195,19.437
1969,13.194,15.368
1970,11.077,16.442
1971,6.996,16.527
1972,8.029,12.988
1973,18.807,8.758
1974,7.418,8.959
1975,6.039,8.619
1976,7.556,6.74
1977,8.541,10.199
1978,7.697,12.899
1979,8.363,13.927
1980,6.232,14.202
1981,10.65,7.533
1982,8.616,15.919
1983,10.962,8.416
1984,6.143,8.735
1985,7.645,8.264
1986,3.476,4.715
1987,1.976,3.394
1988,3.603,6.616
1989,2.424,4.535
1990,3.076,4.912
1991,2.891,2.781
1992,8.626,2.448
1993,5.875,1.002
1994,2.427,2.737
1995,2.431,3.665
1996,5.427,2.351
1997,5.615,1.872
1998,4.18,1.5
1999,5.089,3.505
2000,3.211,4.652
2001,6.216,7.325
2002,10.933,24.659
2003,9.495,5.993
2004,2.414,4.905
2005,2.703,2.897