His slow pace has prompted some hand-wringing among fans, who worry that the 65-year-old writer won't be able to finish the series.
Martin recently told Swedish newspaper on Tages-Anzeiger that he's offended by suggestions that he could die mid-series.
"I find that question pretty offensive, people speculating about my death and my health," he said. "I say f*** you to those people."
2014: The Year in Music [PHOTOS]