My official loss is 60 of 135. 45%. 17 different locations. I usually do worse. Very few that I can't explain. Mites, starvation, nosema and queenless are the most frequent reasons. One interesting queen-line was 14 of 15 successful. They also clustered small and used very,very little honey. Got some barn-busters too. Even with candy blocks on top, some clustered out of reach and dwindled away.
Charlie V