Long before the year 1523, Thomas of Absberg had started to kidnap merchants and imperial diplomats from Nuremberg and Augsburg as they travelled. Although these raids often took place in present-day Lower Franconia, he concealed the whereabouts of those he abducted, hiding them in different castles and changing their locations. He had allies far into Bohemian territory, so he could hide his own whereabouts and elude pursuit. He continued his raids even after 1523, but was eventually murdered in 1531 by a follower. The raids of Hans Thomas Absberg during the period 1519-1530 were documented and fought by the Nuremberg War Office . Feuding at that time was a legitimate means of enforcing one's interests. For the Franconian Imperial Knights, whose importance was waning, it was also a means to combat the power of the emerging territorial states, such as the Bishopric of Bamberg and Burgraviate of Nuremberg, as well their margraviates,  Kulmbach and Ansbach. However, the robber barons often misused this means of dispute, because a feud had inter alia to be properly announced and needed a reasonable justification. This misuse spelt the end of feuding as a legitimate arm of policy. It was replaced by an even more effective peace under the Landfrieden.
Question: How many years did the raids of Hans Thomas Absberg last?
Answer: 11