Complex sentence: The classes of course contained widely differing numbers of people, even though the number of electors was the same for each one: in 1849 the first class constituted 4.7% of the population, the second class 12.7% and the third class 82.6%.
Split into simpler sentences: The classes of course contained widely differing numbers of people even though the number of electors was the same for each one. In 1849, the first class constituted 4.7% of the population, the second class 12.7% and the third class 82.6%.