Z,CH4_m=10.6,C2H6_m=10.2,C2H4_m=11.5
0.066,11.2,16.23,19.46
0.198,13.2,12.4,15.99
0.33,14.2,14.75,17.36
0.462,16.5,16.55,20.4
0.594,17,17.02,23.79
0.726,18.4,17.7,25.3
0.858,20.1,18.82,26.66
0.99,,20.39,28.93

Z,CH4_m=10.6,C2H6_m=10.2,C2H4_m=11.5
0.066,11.2,16.23,19.46
0.198,13.2,12.4,15.99
0.33,14.2,14.75,17.36
0.462,16.5,16.55,20.4
0.594,17,17.02,23.79
0.726,18.4,17.7,25.3
0.858,20.1,18.82,26.66
0.99,NaN,20.39,28.93

Add NaN to experimental data file
Add NaN to experimental data file

This is needed so that we can read the file with a simple Matlab script.