What method was most often used to start the process of amending the U.S Constitution?

The most common method used to start the process of amending the U.S. Constitution is through a two-thirds vote in both houses of Congress, the Senate and the House of Representatives. This method has been employed for the vast majority of amendments ratified since the Constitution's adoption. Alternatively, a constitutional convention can be called by two-thirds of state legislatures, but this method has never been used.