#  pI = 0.68
#  pH      chg
  0.00	  0.00
  0.50	  0.00
  1.00	 -0.00
  1.50	 -0.00
  2.00	 -0.01
  2.50	 -0.02
  3.00	 -0.06
  3.50	 -0.18
  4.00	 -0.41
  4.50	 -0.68
  5.00	 -0.87
  5.50	 -0.96
  6.00	 -0.99
  6.50	 -1.00
  7.00	 -1.00
  7.50	 -1.00
  8.00	 -1.00
  8.50	 -1.00
  9.00	 -1.00
  9.50	 -1.00
 10.00	 -1.00
 10.50	 -1.00
 11.00	 -1.00
 11.50	 -1.00
 12.00	 -1.00
 12.50	 -1.00
 13.00	 -1.01
 13.50	 -1.04
 14.00	 -1.11