Some interesting similiar examples of titles held by a surprisingly large number of people in a short time:
In the life of the Wray of Glentworh Baronetcy, from 1612 to 1809, there were fifteen holders of it. Two held the title for no more than one month, while the last one held it for one year and eighteen days. Some held it for so short a time that they are not even listed as baronets in the family's article in Burke's Extinct Baronetcies, though they are all listed in The Complete Baronetage.
Particularly numerous are the Earls of Suffolk from 1689, when the 3rd Earl died, to 1783, when the 15th Earl succeeded. Horace Walpole noted in a letter to Lady Ossory in 1783 that when he had visited Saffron Walden in 1762, he saw a vault in which there were the coffins of eleven earls and countesses of Suffolk who had died since 1700 (the editor of the Yale edition gives more specifics: they died between 1703 and 1745, and did not include the widow of the 4th Earl, who was buried elsewhere.) He went on to note that there had been seven more deaths since that time (the editor notes that between 1757 and 1783 eight more earls and countess of Suffolk had died, though most of them had not been buried at Walden.)
In continental titles, by the way, there were six ruling Landgraves of Hesse-Homburg between the beginning of 1820 and the end of 1848.