"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.)