Heavily in debt, Clinton lobbied the Duke of Newcastle for profitable employment as an American governor: he was appointed Governor of the Province of New York in July 1741 and arrived in New York in September 1743 to take up his position. Promoted to rear-admiral on 10 December 1743 and vice-admiral on 23 June 1744, he sought to protect New York's Northern border from attack by the French: however liberal members of the New York assembly resisted his proposals as they wanted to maintain trade links with the French and with the Native Americans who were under French influence. James De Lancey, who had initially been his main adviser, turned against him and sought to block the governor's salary. Clinton therefore invited Sir William Johnson to take over responsibility for Native American affairs in 1746 and appointed Cadwallader Colden to be his advisor. Clinton was promoted to full admiral on 15 July 1747. Working with the Mohawk chief Hendrick Theyanoguin, Johnson was able to recruit Mohawk warriors to fight on the side of the British in 1747 during King George's War. After continuing disputes with the assembly over military expenditure and payment of the governor's salary, Clinton resigned as governor in October 1753.
Question: How many months passed between Clinton's promotion to rear-admiral and his promotion to vice-admiral?
Answer: 6