blah.py

import collections
import pprint
import operator

d = collections.defaultdict(int)
z = {}
original = '''FNNVRJAINVMUHZBJLTXFEMNVAINVMUOWUCNVNVRJCKXFWELTNVWXTZMUAIBJ'''
print 'total chars:',len(original)

for c in original:
    d[c] += 1

sorted_x = sorted(d.items(), key=operator.itemgetter(1))

print 'count: '
pprint.pprint(sorted_x)

for key in d:
    z[key] = float(d[key])/float(len(original))

sorted_x = sorted(z.items(), key=operator.itemgetter(1))
print 'frequency: '
pprint.pprint(sorted_x)