数据：
year id_new y l k te
2007 1 12.04719 5.697093 9.952278 1274.853
2004 2 10.95081 4.787492 8.349957 1273.959
2002 3 12.71979 7.351158 12.85178 1276.473
2004 4 9.966462 6.040255 6.709304 1274.2
2005 4 9.312897 6.040255 7.467371 1274.395
2006 4 9.429957 5.480639 7.611843 1274.136
2007 4 8.73311 5.393628 7.541152 1274.072
2006 5 10.7536 4.094345 7.145196 1273.283
2007 5 9.972874 3.912023 6.993933 1273.147
2003 6 8.302762 4.787492 6.192362 1273.404
2004 6 8.517793 4.867535 6.144186 1273.434
2005 6 8.897272 4.867535 6.146329 1273.435
2006 6 9.21682 4.60517 6.829794 1273.472
2007 6 9.001963 4.867535 6.791222 1273.601
2007 7 8.875287 3.806663 6.369901 1272.931
2002 8 10.56359 5.123964 9.25177 1274.369
2003 8 10.45852 5.181784 10.62963 1274.754
2004 8 11.17605 5.298317 8.999619 1274.397
2007 8 11.09133 5.298317 10.3145 1274.735
2004 9 9.838682 5.192957 8.686091 1274.26
2007 10 8.95944 2.484907 7.508239 1272.524
2007 11 9.649498 3.555348 5.620401 1272.605
2002 12 8.726481 4.770685 7.123673 1273.635
2003 12 8.767017 4.564348 7.570443 1273.641
2004 12 9.024372 4.584968 7.665753 1273.676
2005 12 9.146229 4.553877 7.653495 1273.656
2006 12 9.301369 4.49981 8.050385 1273.73
2007 12 9.346967 4.510859 8.313607 1273.803
2000 13 8.93208 4.219508 7.154615 1273.351
2004 14 9.304923 4.060443 7.587817 1273.379
2006 15 10.09046 4.955827 8.306719 1274.037

有没有大神知道是什么问题？数据是面板数据，没有缺失值。