How to estimate Robot density in a country? I'm writing a thesis where a key element is the degree of automation (for Switzerland) through time. 

I was counting on the IFR to get those data but I need to pay 2000k to get them...
Does anyone have an idea of how to estimate that? maybe a proxy? I cannot think of anything...

Thank you for your help
Daron Acemoglu has written a fair bit about the impacts of automation on labour markets. Bearing in mind that mechanization and "robotization" are different in important ways (with that importance increasing as AI and machine learning become more sophisticated and ubiquitous) you could use his work as a starting point.  Certainly, you'd be remiss not to cite it if you're writing a paper.

In https://www.nber.org/papers/w24196, Acemoglu outlines the challenges to the question you're asking and offers a framework of approach.  In https://www.aeaweb.org/articles?id=10.1257/jep.33.2.3, the framework is applied, and there are links to the data which you can look at for insight into how to measure this stuff.