The North Dakota license plate is seen on the backside of a dirty truck outside an oil drilling site in Williston, North Dakota March 12, 2013. North Dakota's booming oil business has quickly ran up against a serious shortage of housing for the thousands of workers who have poured into the state looking to cash in on the Bakken oil formation that has made North Dakota the second-largest oil-producing state after Texas. Picture taken March 12, 2013. REUTERS/Shannon Stapleton (UNITED STATES - Tags: BUSINESS ENERGY ENVIRONMENT COMMODITIES)