For austria: https://www.umweltbundesamt.at/news201221-1

The result is a share of 25.8% (short-term) to 39.3% (long-term) of all employed persons in Austria who could in principle work from home on a permanent or temporary basis.

By overestimating the work-related passenger kilometers, this results in a savings potential of about 300 kilotons of CO2 equivalents per year, if about a quarter of all employed persons in Austria work from home for 40 % of the working time (or 2 out of 5 working days).

Due to undesirable rebound effects, such as an increasing distance between home and work, induced traffic as a result of freed-up capacity, or increased capacities or increased leisure mobility, this potential can increase to 90 kilotons of CO2 equivalents per year.