Lots of charts and plots of the growth of arXiv.org through 2018 are now online at https://arxiv.org/help/stats/2018_by_area/index
In the area I moderate (cs.DS, algorithms and data structures) the number of preprints grew from 1597 in 2017 to 1767 in 2018, but this was a little below the 14% growth rate for arXiv overall, and was far outpaced by the rapid growth in cs.CV (computer vision), cs.LG (machine learning), and cs.CL (natural language processing)..
A Mastodon instance for maths people. The kind of people who make \(\pi z^2 \times a\) jokes.
\) for inline LaTeX, and
\] for display mode.