Manhattan’s residential market was extremely strong in the first three months of the year, according to a report released by appraisal firm Miller Samuel. The report found there was a 73 percent increase in the number of sales in the first quarter over 2006 levels, with 3,474 units selling, up dramatically from the 2,005 that sold this time last year. The number of sales was up a whopping 42 percent from last quarter, and the average sale price rose 5.4 percent. Bonus money, low mortgage rates and the normal increase in sales activity following the winter holidays all contributed to the big numbers. And the forecast going forward looks sunny, too: Jonathan Miller, president and CEO of Miller Samuel, says sales are expected to stay at or above current levels in the second quarter. more By Vanessa Londono