I think it varies from individual pistol to pistol. I have a database of trigger pulls containing thousands of weapons sampled (it was put together by a lawyer who needed it to testify whether or not a particular weapon could have accidentally gone off).
For 35 Berettas, in SA, the min was 4.0 lbs, the max was 6.6lbs, and the average was 5.2 lbs. In DA, the min was 8.8lbs, the max was 15.9 lbs, and an average of 12.2 lbs.
I don't know if the chart takes into account customized pistols with trigger jobs though, or just stock pistols.