In the 1970s Poland's government raised food prices while wages were stagnant. This and other stresses led to protests in 1976 and a subsequent government crackdown on dissent. The KOR, the ROPCIO and other groups began to form underground networks to monitor and oppose the government's behaviour. Labour unions formed an important part of this network. In 1979, the Polish economy shrank for the first time since World War II, by 2 percent. Foreign debt reached around $18 billion by 1980.