The first book of seven, A Game of Thrones, was first published in 1996 and with each succeeding novel in A Song of Ice and Fire series, the wait for the next has been getting longer and longer.
The last gap was six years between fourth book A Feast of Crows and fifth book A Dance with Dragons.
But with the success of the Game of Thrones TV show and other projects Martin has in the works, it’s coming up on seven years since the latter novel was released.
One bored fan on Reddit has used a statistical analysis of book numbers vs original release dates, which saw its quadratic model accurately predict them, within a margin of just 165 days.
Taking into account a delay until the middle of the next decade, the concerned fan pointed out: “Martin is no spring chicken at 69.
“It’s reasonable to worry that he might not be able to finish at this rate and equally reasonable to suspect he doesn’t much care.”
The Winds of Winter is estimated to be released in 2018 or 2019.