Year,Spring_kg_tow,Fall_kg_tow
1963,,79.789
1964,,96.608
1965,,72.778
1966,,29.863
1967,,25.478
1968,20.553,15.407
1969,16.931,8.439
1970,17.127,13.508
1971,8.883,5.596
1972,7.379,8.477
1973,15.375,9.787
1974,17.707,3.997
1975,8.212,11.934
1976,15.717,35.761
1977,26.469,27.598
1978,31.273,18.109
1979,19.697,32.057
1980,53.83,22.038
1981,38.107,14.264
1982,13.14,7.305
1983,13.213,5.751
1984,7.445,4.476
1985,11.143,3.584
1986,5.9,5.015
1987,5.595,2.559
1988,3.431,5.31
1989,4.697,4.453
1990,7.572,2.624
1991,4.388,0.94
1992,1.408,3.169
1993,2.48,4.33
1994,3.637,2.931
1995,5.723,10.659
1996,25.727,4.113
1997,18.504,6.513
1998,6.116,5.752
1999,7.745,33.086
2000,17.881,15.405
2001,6.11,19.995
2002,22.331,36.304
2003,15.611,23.041
2004,41.357,55.799
2005,17.733,39.409