Complex sentence: Dave Grohl has appeared 32 times throughout the countdown, including the top spot on two occasions (1991,2002), though 13 of those appearances were from the Hottest 100 Of All Time countdowns.
Split into simpler sentences: Dave Grohl has appeared 32 times throughout the countdown including the top spot on two occasions (1991,2002). Although, 13 of these appearances are from the Hottest 100 Of All Time countdowns.