Year,R_index_knum_tow_sum,R_index_knum_tow_spr
1975,0.157155208,8.584514338
1976,2.426769446,58.7511862
1977,3.173905059,92.38259505
1978,1.695809003,6.834690515
1979,0.827624692,49.92236854
1980,3.875395113,35.99276177
1981,13.78682437,261.778065
1982,1.445222404,25.72166236
1983,0.655992192,22.71111431
1984,6.641981667,109.9170252
1985,1.290587559,22.74741639
1986,3.189662568,17.79118064
1987,0.131157131,7.254206285
1988,6.374132082,3.060709381
1989,14.57678859,216.0022184
1990,1.767620479,4.166076527
1991,0.046724125,7.76082579
1992,5.373568781,1.231016404
1993,0.045952453,0.968380374
1994,2.739083609,3.67130786
1995,3.6130377,5.26847114
1996,0.155219746,9.156887088
1997,1.800902002,2.362804531
1998,2.177851683,2.628180262
1999,3.790679691,11.89722051
2000,0.76990719,1.804069935
2001,5.686166118,3.389627213
2002,5.692583288,2.448465247
2003,21.88619923,27.84633205
2004,1.767518837,1.825788689
2005,13.97468666,15.09948367