improvements to DOI usage, open3can

[StephanJanosch]

The pricture below shows better imho what the real message for Germany is.

The notebook does not count the 1 (None at all) and the numbers are quite small.

[Oliph]

I have seen an error with the 1 (not at all), there is an invisible space in it. should be fix in the next push

[StephanJanosch]

awesome! Thanks!