Year,Avg_num_tow_female,Avg_num_tow_male
1981,0.1216,0.1058
1982,0.2962,0.2246
1983,0.7246,0.7157
1984,0.3832,0.2007
1985,1.1159,0.9441
1986,1.2042,1.2313
1987,0.4284,0.5586
1988,0.8453,0.6290
1989,1.1513,1.3714
1990,0.9749,1.4072
1991,1.1221,1.1292
1992,0.5836,0.7447
1993,0.7011,0.8084
1994,2.0183,2.2498
1995,1.2525,1.9238
1996,2.8412,2.9416
1997,1.8905,1.6248
1998,1.8912,1.7688
1999,3.2372,2.1443
2000,2.2496,2.3095
2001,1.5237,1.1253
2002,2.6722,1.6308
2003,1.1924,0.7593
2004,2.1071,2.5804
2005,0.8414,0.8184
2006,1.3393,1.1890