densely populated neighborhoods were located, dropped, while the population of the new 17th and 20th arrondissements, on the edges of the city, grew rapidly. Haussmann's defenders noted that he built far more buildings than he tore down: he demolished 19,730 buildings, containing 120,000 lodgings or apartments, while building 34,000 new buildings, with 215,300 new apartments and lodgings. French historian Michel Cremona wrote that, even with the increase in population, from 949,000 Parisians in 1850 to 1,130,500 in 1856, to two million in 1870, including those in the newly annexed eight arrondissements around the city, the number of housing units grew faster than the population. Recent studies have also shown that the proportion of Paris housing occupied by low-income Parisians did not decrease under Haussmann, and that the poor were not driven out of Paris by Haussmann's renovation. In 1865 a survey by the prefecture of Paris showed that 780,000 Parisians, or 42 percent of the population, did not pay taxes due to their low income. Another 330,000 Parisians or 17 percent, paid less than 250 francs a month rent. Thirty-two percent of the Paris housing was occupied by middle-class families, paying rent between 250 and 1500 francs. Fifty thousand Parisians were classified as rich, with rents over 1500 francs a month, and occupied just three percent of the residences. Other critics blamed Haussmann for the division of Paris into rich and poor neighborhoods, with the poor concentrated in the east and the middle class and wealthy in the west. Haussmann's defenders noted that this shift in population had been underway since the 1830s, long before Haussmann, as more prosperous Parisians moved to the western neighborhoods, where there was more open space, and where residents benefited from the prevailing winds, which carried the smoke from Paris's new industries toward the east. His defenders also noted that Napoleon III and Haussmann made a special point to build an equal number of new boulevards, new sewers, water supplies, hospitals, schools, squares, parks and gardens in the working class eastern arrondissements as they did in the western neighborhoods. A form of vertical stratification did take place in the Paris population due to Haussmann's renovations. Prior to Haussmann, Paris buildings usually had wealthier people on the second floor (the "etage noble"), while middle class and lower-income tenants occupied the top floors. Under Haussmann, with the increase in rents and greater demand for housing, low-income people