Web document 3.5. Normalized frequency of the amino acids. From http://www.expasy.ch/sprot/relnotes/relstat.html. These values (in percent) are reasonably similar to the results described by Dayhoff et al. (1978).

 
Leu (L) 9.65   Asp (D) 5.34
Ala (A) 7.88   Pro (P) 4.82
Gly (G) 6.96   Asn (N) 4.12
Ser (S) 6.83   Gln (Q) 3.95
Val (V) 6.73   Phe (F) 3.95
Glu (E) 6.66   Tyr (Y) 3.01
Lys (K) 5.93   Met (M) 2.39
Ile (I) 5.91   His (H) 2.29
Arg (R) 5.42   Cys (C) 1.50
Thr (T) 5.40   Trp (W) 1.13