Manual Pages  — CAESAR

The optional numerical argument rotation may be used to specify a specific rotation value. If invoked as rot13, a rotation value of 13 will be used.

The frequency (from most common to least) of English letters is as follows: ETAONRISHDLFCMUGPYWBVKXJQZ

Their frequencies as a percentage are as follows: E(13), T(10.5), A(8.1), O(7.9), N(7.1), R(6.8), I(6.3), S(6.1), H(5.2), D(3.8), L(3.4), F(2.9), C(2.7), M(2.5), U(2.4), G(2), P(1.9), Y(1.9), W(1.5), B(1.4), V(.9), K(.4), X(.15), J(.13), Q(.11), Z(.07).