#  pI = undefined
#  pH      chg
  0.00	  0.05
  0.50	  0.02
  1.00	  0.00
  1.50	 -0.00
  2.00	 -0.01
  2.50	 -0.04
  3.00	 -0.10
  3.50	 -0.27
  4.00	 -0.54
  4.50	 -0.79
  5.00	 -0.92
  5.50	 -0.97
  6.00	 -0.99
  6.50	 -1.00
  7.00	 -1.00
  7.50	 -1.01
  8.00	 -1.02
  8.50	 -1.05
  9.00	 -1.15
  9.50	 -1.36
 10.00	 -1.70
 10.50	 -2.06
 11.00	 -2.43
 11.50	 -2.73
 12.00	 -2.90
 12.50	 -2.98
 13.00	 -3.03
 13.50	 -3.12
 14.00	 -3.33