Compared with the US Constitution, how difficult is it to amend state constitutions?

The Constitution is difficult to amend because it requires a supermajority of either members of Congress or a supermajority of state legislatures to propose a new amendment for ratification. Even after acquiring the requisite two-thirds of either group to propose the amendment, it then has to be ratified by 75 percent of the states, either by their legislatures or state Constitutional conventions.