added a graph "transmission.png", stacked bar plot indicating transmission level values: not sure whether there is any interesting information in it, risk levels 2 and 4 seem not to be indicated at all, and 7 relatively rarely.
Thanks for your work! Your contribution is now fully integrated. I made some minor adjustments to be more consistent with the layout of the generated plot.
added a graph "transmission.png", stacked bar plot indicating transmission level values: not sure whether there is any interesting information in it, risk levels 2 and 4 seem not to be indicated at all, and 7 relatively rarely.