The mapping is as follows (ψ is practically omitted):
VMS Greek
-------------------
'o': 'α', # 13.10%
'e': 'ο', # 10.44%
'h': 'ι', # 9.76%
'y': 'ε', # 9.38%
'l': 'π', # 7.90%
'a': 'σ', # 7.72%
'c': 'τ', # 6.29%
'd': 'ν', # 4.82%
'i': 'υ', # 4.52%
'k': 'κ', # 3.77%
'r': 'ρ', # 3.42%
's': 'η', # 3.32%
't': 'μ', # 2.85%
'n': 'λ', # 2.47%
'q': 'ω', # 2.16%
'p': 'γ', # 1.75%
'm': 'δ', # 1.54%
'f': 'θ', # 1.48%
'g': 'χ', # 0.78%
'x': 'φ', # 0.77%
'z': 'β', # 0.75%
'v': 'ζ', # 0.41%
'j': 'ξ', # 0.40%
'w': 'ψ', # 0.20%
Of course, this is not reliable.
VMS Greek
-------------------
'o': 'α', # 13.10%
'e': 'ο', # 10.44%
'h': 'ι', # 9.76%
'y': 'ε', # 9.38%
'l': 'π', # 7.90%
'a': 'σ', # 7.72%
'c': 'τ', # 6.29%
'd': 'ν', # 4.82%
'i': 'υ', # 4.52%
'k': 'κ', # 3.77%
'r': 'ρ', # 3.42%
's': 'η', # 3.32%
't': 'μ', # 2.85%
'n': 'λ', # 2.47%
'q': 'ω', # 2.16%
'p': 'γ', # 1.75%
'm': 'δ', # 1.54%
'f': 'θ', # 1.48%
'g': 'χ', # 0.78%
'x': 'φ', # 0.77%
'z': 'β', # 0.75%
'v': 'ζ', # 0.41%
'j': 'ξ', # 0.40%
'w': 'ψ', # 0.20%
Of course, this is not reliable.

