How old was Benjamin Franklin when he died?

There is some debate as to the date on which Benjamin Franklin was born. Most sources mark the date as January 17th, 1706. However, in 2006 the Boston Globe claimed that Benjamin Franklin was actually born on January 6th, 1706. There is a reasonably straightforward explanation for these different dates. In September, 1752, in order to be in line with the rest of Europe, Great Britain changed from the Julian calendar to the Gregorian calendar. In the process, Great Britain and its colonies in America moved their calendars forward by eleven days. Benjamin Franklin accordingly moved his birthday from January 6th to January 17th.
Franklin died, indisputably, on April 17th, 1790, less than three years after signing the American Constitution. He was, therefore, eighty-four years and three months old, give or take a week, when he died.