In the East, the intended gains of Lebensraum were never attained as fluctuating front-lines and Soviet scorched earth policies denied resources to the German invaders. Unlike in the West, the Nazi racial policy encouraged extreme brutality against what it considered to be the "inferior people" of Slavic descent; most German advances were thus followed by mass executions. Although resistance groups formed in most occupied territories, they did not significantly hamper German operations in either the East or the West until late 1943. In Asia, Japan termed nations under its occupation as being part of the Greater East Asia Co-Prosperity Sphere, essentially a Japanese hegemony which it claimed was for purposes of liberating colonised peoples. Although Japanese forces were originally welcomed as liberators from European domination in some territories, their excessive brutality turned local public opinion against them within weeks. During Japan's initial conquest it captured 4,000,000 barrels  of oil  left behind by retreating Allied forces, and by 1943 was able to get production in the Dutch East Indies up to 50 million barrels , 76 per cent of its 1940 output rate.
Question: How many more million barrels of oil was Japan producing per year in 1943 than it captured from retreating Allied forces during the initial conquest?
Answer: 46