A gauge of New York-area manufacturing remained close to two-year high levels in March, according to data released Wednesday. The Empire State manufacturing survey slipped to 16.4 in March, down only 2.3 points from a two-year high of 18.7 in February, the New York Fed said. Economists had expected a 15.4 reading according to a survey by Econoday, in the gauge where readings above zero indicate improving conditions. The new orders index climbed 7.8 points to 21.3 in March, its highest level in several years. The unfilled orders index rose to 14.2, its highest level in more than a decade. The Empire State is the first of the regional manufacturing surveys to be released; the Philadelphia Fed survey comes out Thursday.