I notice thre's a red splotch over my old home town of Brooklyn (NY) too. When I was in my early 20's (early 1970's) a friend and I got into a friendly barroom argument in Bay Ridge Brooklyn about whether 5th avenue or 3rd avenue had more bars.
We decided that the only way to settle the argument was to spend a Friday night doing a walking pub crawl of 5th Avenue and the next night doing 3rd Avenue. The commercial district runs from about 65th Street to 95th street on both blocks.
I actually do not remember which won, but the final score was something like 24 bars to 23 bars (we stopped in a good many of them..). We didn't count grocery stores, but there couldn't have been more than 5 of each on that stretch.
In 2010 it's still a bar hoppers heaven, but instead of lots of what we used to call Old Man Bars and some singles spots, it's mostly more upscale and restuarant-y than 40 years ago.