Continental Air unit revenue up 4.5-5.5 pct in Mar = = = = Thursday April 1, 6:44 PM EST = NEW YORK, April 1 (Reuters) - Unit revenue for Continental Airlines (CAL)= , a key measure of industry performance, rose in March, the carrier said = on Thursday. The Houston-based company estimated that March revenue per available seat= mile increased between 4.5 percent and 5.5 percent from the same month a= year earlier. In February, revenue per available seat mile decreased 2.5= percent from a year ago. Systemwide load factor, or the percentage of seats filled in planes by pa= ying passengers, was 74.9 percent, up 0.7 percentage point from a year ea= rlier, Continental said in a statement. = =A92004 Reuters Limited. = Roger EWROPS