All the figures published in the article and sub-figure files are provided in
csv format. Figure data is named according to the corresponding figure number
and sub-figure letter used in the paper.

Line plots have data stored in a single file for each figure.  For example:
- 1a.csv: all data for Fig. 1a

Contour plots have data stored in three separate files for each figure.  For example:
- 1b_X.csv: x-axis data for Fig. 1b
- 1b_Y.csv: y-axis data for Fig. 1b
- 1b_Z.csv: z-axis data (contour data) for Fig. 1b

The data associated with these figures can be easily retrieved by opening the
csv files in any editor.