#  pI = 8.40
#  pH      chg
  0.00	  1.00
  0.50	  1.00
  1.00	  1.00
  1.50	  1.00
  2.00	  1.00
  2.50	  1.00
  3.00	  1.00
  3.50	  1.00
  4.00	  1.00
  4.50	  1.00
  5.00	  1.00
  5.50	  1.00
  6.00	  0.99
  6.50	  0.96
  7.00	  0.90
  7.50	  0.72
  8.00	  0.38
  8.50	 -0.10
  9.00	 -0.67
  9.50	 -1.26
 10.00	 -1.69
 10.50	 -1.89
 11.00	 -1.99
 11.50	 -2.07
 12.00	 -2.22
 12.50	 -2.55
 13.00	 -3.07
 13.50	 -3.71
 14.00	 -4.32