Frequency counts from plain text versions of these:

http://www.gutenberg.org/etext/1661
http://www.gutenberg.org/etext/1342

A = 1374     a = 77072     78446
B = 1728     b = 14220     15948
C = 1056     c = 23604     24660
D = 868      d = 40836     41704
E = 1209     e = 123974    125183
F = 396      f = 21059     21455
G = 439      g = 17924     18363
H = 1988     h = 61912     63900
I = 6545     i = 62995     69540
J = 474      j = 958       1432
K = 197      k = 6766      6963
L = 1089     l = 38446     39535
M = 2524     m = 24565     27089
N = 698      n = 67183     67881
O = 690      o = 74960     75650
P = 517      p = 15063     15580
Q = 22       q = 1063      1085
R = 475      r = 57903     58378
S = 1409     s = 60104     61513
T = 2156     t = 85576     87732
U = 154      u = 28708     28862
V = 134      v = 10246     10380
W = 1447     w = 22456     23903
X = 10       x = 1450      1460
Y = 860      y = 21831     22691
Z = 7        z = 1087      1094

e = 125183
t = 87732
a = 78446
o = 75650
i = 69540
n = 67881
h = 63900
s = 61513
r = 58378
d = 41704
l = 39535
u = 28862
m = 27089
c = 24660
w = 23903
y = 22691
f = 21455
g = 18363
b = 15948
p = 15580
v = 10380
k = 6963
x = 1460
j = 1432
z = 1094
q = 1085

Huffman tree:
569515
   306681
      159968
         81522
            d = 41704
            39818
               f = 21455
               g = 18363
         a = 78446
      146713
         o = 75650
         71063
            l = 39535
            31528
               b = 15948
               p = 15580
   262834
      137421
         i = 69540
         n = 67881
      125413
         h = 63900
         s = 61513
420912
   239512
      e = 125183
      114329
         r = 58378
         55951
            u = 28862
            m = 27089
   181400
      93668
         48563
            c = 24660
            w = 23903
         45105
            y = 22691
            22414
               12034
                  k = 6963
                  5071
                     2892
                        x = 1460
                        j = 1432
                     2179
                        z = 1094
                        q = 1085
               v = 10380
      t = 87732

char <= 'i'
   e = 125183
   a = 78446
   i = 69540
   h = 63900
   d = 41704
   c = 24660
   f = 21455
   g = 18363
   b = 15948
   char <= 't'
      t = 87732
      o = 75650
      n = 67881
      s = 61513
      r = 58378
      l = 39535
      m = 27089
      p = 15580
      k = 6963
      j = 1432
      q = 1085
   char > 't'
      u = 28862
      w = 23903
      y = 22691
      v = 10380
      x = 1460
      z = 1094