Holiday homes have quite the impact in many parts of Wales.
Occupancy ratings per house seem to be quite low on average [1], but weirdly I can’t seem to find any figures for overall occupancy.
[1] https://www.ons.gov.uk/peoplepopulationandcommunity/housing/...
Edit: clarification
Maybe on a hyper local basis, but beware there will be negatives with flushing them out too.
On a national scale I'm afraid it's just not statistically significant.