Assuming an 8 hour work day that's closer to 30%. Even at 12 hours that's 20% and that's not including weekends.
5 / (8*10*5/7) = 0.875. (excluding weekends)
If you take into account annual leaves, say 25 days, it is still below 10%
Assuming an 8 hour work day that's closer to 30%. Even at 12 hours that's 20% and that's not including weekends.