There is a 1/6 possibility for an A and a 5/6 chance for a C to occupy each position in the triplet.
By examining the percentages of amino acids incorporated into the protein synthesized, probable base composition for some codons can be proposed.
Proline appears 69% of the time, so it may be encoded by CCC (57.9%) and one codon consisting of 2C:1A (11.6%).
Histidine, at 14%, is probably coded by one 2C:1A (11.6%) and one 1C:2A (2.3%).
Threonine, at 12%, is likely coded by only one 2C:1A.
Asparagine and glutamine each seem to be coded by one of the 1C:2A codons, and lysine by AAA.