What would be the best way to show table/database growth?
There's a hierarchy in analytics value that goes descriptive, diagnostic, predictive, prescriptive. What your question talks about is &quot;descriptive.&quot; I think you should aim for &quot;predictive.&quot;
You're collecting these numbers because you're concerned about exhausting some resource - disk space, backup size, sequential IDs, whatever. That's what will cause problems, not the absolute size of the table per se. Therefore that is what should be reported.
The output should be

Extrapolating over the last 4 months, Disk D: will be full by Jan 2021.
Last month's report predicted Feb 2021.

There are many ways to calculate the exhaustion point. Simple linear extrapolation is one. I've used Monte Carlo to some success.