I am currently looking into WW1 casualties from the Uists. By Uists I mean all islands from Berneray to Vatersay. However, of the 12,266 people in the 1911 census of the Uists, 426 (3.4%) lost their lives in the Great War. That was 7% of all men.
For Lewis, out of a population of 29,629, losses amounted to 1,285 (4.3%), equating to 9.4% of all men.
For Harris, out of a population of 4,849, losses amounted to 126 (2.6%), which was 5.6% of all men.
Small wonder these islands were referred to as the Isles of Sorrow...