Last week was the news that Manhattan apartment rents, despite all logic, continue to climb: The average studio is now closing in on $2,000 a month. Now comes word that the sales market, also defying common wisdom, is following suit. Co-op and condo prices jumped 8 percent during the second quarter of 2007; the average New York City apartment — that’s all five boroughs — now costs, drumroll, $831,000. Of course, if you’re not entirely in thrall to the 212 area code, where the average apartment goes for $1.2 million, things aren’t quite so dire. The average Brooklyn flat clocks in at a third that price, a much more reasonable $484,000, and in Queens prices are actually down 4.3 percent. In another milestone, Manhattan’s per-square-foot average has crossed the thousand-dollar barrier: It’s now $1,083. All this madness stands in such stark contrast to the rest of the country; one could get the impression New York is the only place in the United States anyone actually wants to live. To which we can only say: Duh.