The first United States occupation of the Dominican Republic lasted from 1916 to 1924. It was one of the many interventions in Latin America undertaken by the military forces of the United States in the 20th century. On May 13, 1916, Rear Admiral William B. Caperton forced the Dominican Republic's Secretary of War Desiderio Arias, who had seized power from Juan Isidro Jimenes Pereyra, to leave Santo Domingo by threatening the city with naval bombardment. The first major engagement occurred at Las Trencheras on June 27. There the Dominican rebels had dug trenches on two hills, one behind the other, blocking the road to Santiago. The field guns of Captain Chandler Campbell's 13th Company, along with a machine gun platoon, took position on a hill commanding the enemy trenches and opened fire. Under the cover of this fire, the Marine infantry charged the defenders' first line, covered until the last possible moment by the artillery barrage. The insurgents fled to their trenches on the second hill. They rallied there briefly, then broke and ran again as the American field guns resumed shelling. Within 45 minutes from the opening artillery shots, the Marines, at a cost to themselves of one killed and four wounded, had overrun the enemy positions. They found no dead or weapons in the trenches but later discovered five rebel bodies in the nearby woods. This engagement set the pattern for most Marine contacts with hostile forces in the Dominican Republic. Against Marine superiority in artillery, machine guns, small-unit maneuver, and individual training and marksmanship, no Dominican force could hold its ground.

Based on the above article, answer a question. The first United States occupation of the Dominican Republic lasted how many years?
8