The timeline of those thirteen years has the following entries:
146 B.C. Third Punic War ends
140-134 B.C War with the Numantines
140 B.C. Agrarian reform introduced by Laelius and withdrawn
139 B.C. Law passed to use written ballots in voting for the first time
139 B.C. Shortage of corn in Rome. Efforts to build up supplies were blocked
137 B.C. Mancinus defeated by the Numantines and is forced to surrender
136 B.C. Mancinus put on trial, found guilty, and banished
136 B.C. Slave rebellion in Sicily
134 B.C. Scipio Aemilianus takes an army to Spain and defeats the Numantines
133 B.C. The tribunate of Tiberius Gracchus