Glancing at the list it seems pretty flawed; Crater Lake's cataclysmic eruption was a VEI 7, not 8...I've never seen it classified as a supervolcano. The Australian volcano is very old and really can't be considered as potentially active. Some of the others listed were not VEI=8 eruptions either.
That's the only list I found. I don't know about it's accuracy.