subtract 10%iles  -0.00376391      0.00000    0.0121307    0.0352054
    0.0627468    0.0991726     0.153103     0.249628     0.502979
diff 10%iles    -0.190253   -0.0738032   -0.0320907  -0.00837183      0.00000
   0.00531101    0.0290188    0.0710613     0.187210
stardiff 10%iles   -0.0293009   -0.0107033  -0.00376882      0.00000
      0.00000   0.00379337   0.00867735    0.0161893    0.0347123
stardiff contour -excluded 0.005   -0.0293009    0.0347123