Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

[Q]: Passage: The most useful instrument for analyzing the performance of steam engines is the steam engine indicator. Early versions were in use by 1851, but the most successful indicator was developed for the high speed engine inventor and manufacturer Charles Porter by Charles Richard and exhibited at London Exhibition in 1862. The steam engine indicator traces on paper the pressure in the cylinder throughout the cycle, which can be used to spot various problems and calculate developed horsepower. It was routinely used by engineers, mechanics and insurance inspectors. The engine indicator can also be used on internal combustion engines. See image of indicator diagram below (in Types of motor units section). Question: What year saw the earliest recorded use of the steam engine indicator?
[A]: 1851


[Q]: Passage: Studies on income inequality and growth have sometimes found evidence confirming the Kuznets curve hypothesis, which states that with economic development, inequality first increases, then decreases. Economist Thomas Piketty challenges this notion, claiming that from 1914 to 1945 wars and 'violent economic and political shocks' reduced inequality. Moreover, Piketty argues that the 'magical' Kuznets curve hypothesis, with its emphasis on the balancing of economic growth in the long run, cannot account for the significant increase in economic inequality throughout the developed world since the 1970s. Question: Who challenges the notion of the Kuznets curve hypothesis?
[A]: Thomas Piketty


[Q]: Passage: Throughout its existence, Warsaw has been a multi-cultural city. According to the 1901 census, out of 711,988 inhabitants 56.2% were Catholics, 35.7% Jews, 5% Greek orthodox Christians and 2.8% Protestants. Eight years later, in 1909, there were 281,754 Jews (36.9%), 18,189 Protestants (2.4%) and 2,818 Mariavites (0.4%). This led to construction of hundreds of places of religious worship in all parts of the town. Most of them were destroyed in the aftermath of the Warsaw Uprising of 1944. After the war, the new communist authorities of Poland discouraged church construction and only a small number were rebuilt. Question: Of Warsaw's inhabitants in 1901, what percentage was Catholic?
[A]:
56.2%