add "y/o/y growth" column to table

[ltalirz]

Thoughtful suggestion by the reviewer

The citation trend was a popular comment in the paper, adding a sort by year-over-year growth would be useful.

Currently, the table only uses citation data from the selected year.
Growth data involves data from other years, so that would require some change to the data layout.

Perhaps one should also start looking into precomputing some data - so far, everything is computed from the citation data on the fly.