#  pI = undefined
#  pH      chg
 0.0	  1.0
  0.5	  1.0
  1.0	  1.0
  1.5	  1.0
  2.0	  1.0
  2.5	  1.0
  3.0	  1.0
  3.5	  1.0
  4.0	  1.0
  4.5	  1.0
  5.0	  1.0
  5.5	  1.0
  6.0	  1.0
  6.5	  1.0
  7.0	  1.0
  7.5	  1.0
  8.0	  0.9
  8.5	  0.8
  9.0	  0.6
  9.5	  0.3
 10.0	  0.1
 10.5	  0.0
 11.0	  0.0
 11.5	  0.0
 12.0	  0.0
 12.5	  0.0
 13.0	  0.0
 13.5	  0.0
 14.0	  0.0