days    survival
   0    0.985
  72    0.985
 125    0.971
 127    0.956
 133    0.942
 142    0.927
 151    0.913
 154    0.898
 176    0.884
 184    0.869
 229    0.855
 251    0.840
 256    0.826
 320    0.811
 362    0.797
 391    0.782
 414    0.768
 422    0.753
 434    0.739
 441    0.724
 465    0.709
 471    0.695
 495    0.680
 544    0.665
 584    0.650
 645    0.634
 659    0.619
 749    0.604
 788    0.589
 803    0.573
 812    0.557
1020    0.539
1042    0.522
1151    0.503
1239    0.484
1579    0.447
1606    0.409
3900    0.409