"Onsets and Terminations of Democracy, 1955-2010.xls" by Jay Ulfelder:
https://dataverse.harvard.edu/file.xhtml?fileId=2420019&version=RELEASED&version=.0
A nearly 300-row spreadsheet showing the flipflops of democracy↔︎autocracy, from Albania, Argentina, Armenia to Yugoslavia, Zambia, and Zimbabwe, including numerous notes about what happened and who did it.
Chilling.
(https://gist.github.com/fasiha/cab949bc04da155d1671c16634eae7c6 is my readable browseable version for the convenience of the spreadsheet-challenged, like me.)
I forgot that what I was primarily interested in this (and Jay's subsequent work like https://blog.koto.ai/2018/03/12/tenure-track-china-in-comparative-perspective/) was concrete quantitative ways of describing a country's government as autocratic, or how to objectively say when a government "falls".
An art project that someone could do is, a crowdsource app letting visitors vote how long each country that currently "exists" (including Taiwan, Palestine, etc.) will last, for some criterion or 3rd party analysis like http://oefresearch.org/datasets/reign