Samuel Shute  was an English military officer and royal governor of the provinces of Massachusetts and New Hampshire.  After serving in the Nine Years' War and the War of the Spanish Succession, he was appointed by King George I as governor of Massachusetts and New Hampshire in 1716.  His tenure was marked by virulent disagreements with the Massachusetts assembly on a variety of issues, and by poorly conducted diplomacy with respect to the Native American Wabanaki Confederacy of northern New England that led to Dummer's War . Although Shute was partly responsible for the breakdown in negotiations with the Wabanakis, he returned to England in early 1723 to procure resolutions to his ongoing disagreements with the Massachusetts assembly, leaving conduct of the war to Lieutenant Governor William Dummer.  His protests resulted in the issuance in 1725 of the Explanatory Charter, essentially confirming his position in the disputes with the assembly.  He did not return to New England, being replaced as governor in 1728 by William Burnet, and refused to be considered for reappointment after Burnet's sudden death in 1729. Thomas Hutchinson , in his history of Massachusetts, described Shute's tenure as governor as the most contentious since the Antinomian Controversy of the 1630s.
Question: How many years after the issuance of the Explanatory Charter did William Burnet replace Shute as governor?
Answer: 3