While majority of the unrest occurred in 1905, until 1906-1907 worker unrest, demonstrations and occasional armed clashes continued to occur in Poland. Strikes in Łódź continued until mid-1906, when only the large Russian military presence and mass layoffs of striking workers from the factories pacified the city. The unrest in Poland forced the Russians to keep an army of 250,000-300,000 soldiers there - an army even larger than the one fighting the Japanese in the east. Piłsudski's Combat Organization of the Polish Socialist Party, founded in 1904, and which contributed to escalation of some of the hostilities, became more active during the next few years, starting its campaign of assassinations and robberies mostly from 1906 onward, although they grew much weaker near the end of the decade. Piłsudski's faction was temporarily weakened, and PPS split, although by 1909 Piłsudski's faction again regained prominence on the Polish underground political scene. Piłsudski eventually succeeded in securing Polish independence, and became an important political figure in interwar Poland. Another consequence was the evolution of Polish political parties and thought. National consciousness had risen among the Polish peasants. Despite the failure of the most radical of conceptions, the Russian government conceded to some of the demands, both in the social and in the political science, counteracting the defeatist feelings among many Poles who were still reminiscent about the total defeat of the previous uprisings; in particular, russification was partially reversed in education in Poland.
Question: How many years after its founding did Piłsudski's Combat Organization of the Polish Socialist Party start a campaign of assassinations and robberies?
Answer: 2