HEMPSTEAD - Officials say the number of tickets written by Nassau police officers has sharply declined from last year, and now County Executive Ed Mangano (R-Nassau) wants to know what's behind the ticket tumble. Police say that so far, 110,000 tickets have been issued in 2011. That's a 28-percent drop compared to the same eight-month period in 2010, officials report. According to a spokesman for the police commissioner, Mangano has ordered a complete review to determine why so many fewer tickets have been written.PBA President James Carver says tickets are down because there are fewer cops on the streets. He says since last year, the department has lost about 150 police officers due to downsizes and layoffs.