NEW YORK -- There was a time when the neighborhood hospital was a cornerstone of New York City life. But for a growing number of city residents, the trip to have an appendix taken out or get treatment for a broken leg is increasingly being measured in miles rather than blocks. Since 2000, 19 hospitals across the city have closed due to financial pressures, and nos. 20 and 21 are underway. It's part of a long-simmering trend in health care, experts say: Small, independent hospitals, especially those that serve the poor, are finding it hard to pay the bills.