In the period between the two world wars, the Danish navy  had low priority for the politicians, especially between 1929 and 1942 under Thorvald Stauning. During the first year of the German occupation , the navy assisted the occupying German forces with minesweeping, because of the political demand of keeping the infrastructure  up and running. The tensions between the German soldiers and the Danish armed forces rose slowly and, on 29 August 1943, they managed to scuttle 32 of its larger ships, while Germany succeeded in seizing 14 of the larger and 50 of the smaller vessels. This was due to a secret order, given directly to the captains by word of mouth by commander of the navy, Vice Admiral A. H. Vedel "to try to flee to the nearest neutral or nazi-opposed port. If that was not possible, the ship should be scuttled at as deep a location as possible". The Germans later succeeded in raising and refitting 15 of the sunken ships. A number of vessels had been ordered to attempt to escape to Swedish waters, and 13 succeeded. The fleet flagship, Niels Juel, attempted to break out in the Battle of Isefjord but the crew was forced to beach and partly scuttle her. The score for the larger vessels was therefore: 32 vessels were sunk, 2 were in Greenland, 4 reached Sweden, 14 were captured by the Germans. As for the smaller vessels: 9 "patruljekuttere" reached Sweden, 50 others were captured by the Germans. By the autumn of 1944, these ships officially formed a Danish naval flotilla in exile. In September 1943, A. H. Vedel was fired by order of the prime minister Vilhelm Buhl because of his hostile actions towards the Germans.
Question: How many years did Thorvald Stauning rule in Denmark?
Answer: 13