Estimated values for CH4 I from the polynomial in:
Fray, N., and B. Schmitt 2009.  Sublimation of ices of astrophysical interest: A bibliographic review.  Planet. Space Sci. 57, 2053-2080.
T(K)     P(bar)
30.00   4.38e-13
31.00   1.55e-12
32.00   5.05e-12
33.00   1.54e-11
34.00   4.38e-11
35.00   1.18e-10
36.00   3.01e-10
37.00   7.29e-10
38.00   1.69e-09
39.00   3.75e-09
40.00   7.99e-09
41.00   1.64e-08
42.00   3.27e-08
43.00   6.29e-08
44.00   1.18e-07
45.00   2.14e-07
46.00   3.79e-07
47.00   6.56e-07
48.00   1.11e-06
49.00   1.83e-06
50.00   2.98e-06
51.00   4.74e-06
52.00   7.40e-06
53.00   1.14e-05
54.00   1.72e-05
55.00   2.56e-05
56.00   3.77e-05
57.00   5.46e-05
58.00   7.81e-05
59.00   1.10e-04
60.00   1.54e-04
61.00   2.13e-04
62.00   2.91e-04
63.00   3.94e-04
64.00   5.28e-04
65.00   7.02e-04
66.00   9.24e-04
67.00   1.21e-03
68.00   1.56e-03
69.00   2.01e-03
70.00   2.57e-03
71.00   3.26e-03
72.00   4.10e-03
73.00   5.13e-03
74.00   6.39e-03
75.00   7.90e-03
76.00   9.71e-03
77.00   1.19e-02
78.00   1.44e-02
79.00   1.75e-02
80.00   2.11e-02
81.00   2.52e-02
82.00   3.01e-02
83.00   3.58e-02
84.00   4.24e-02
85.00   5.00e-02
86.00   5.87e-02
87.00   6.86e-02
88.00   8.00e-02
89.00   9.29e-02
90.00   1.08e-01
