According to the statistic table if you have 10 trumps it is excellent news. 22.70% of the time your opponent has 8 trumps, 47.24% of the time your opponent has 9 trumps, 23.39% of the time your opponent has 10 trumps, 5.88% of the time your opponent has 11 trumps, 0.81% of the time your opponent has 12 trumps. About 23% of the time your opponent has the same number of trump as you have which is 10. About 70% of the time opponent has less then 10 trumps. With 10 trumps you always bid up to the 4 level. Never bid to the 5 level. If your opponent bid to the 5 level, you should almost always double unless you have other reason that clearly indicate you should not. Statistically more then 90% of the time your opponent will go down according to the Law and the statistical data of a general hand. Double dummy analysis says 10 trumps are superior as hand distribution. It is even better then 11 trumps.
