The bars are quartiles, so 25% of the probability mass is for ~53 years away or closer. Note that timelines for the HLMI variant of the question[1], which was

The bars are quartiles, so 25% of the probability mass is for ~53 years away or closer. Note that timelines for the HLMI variant of the question[1], which was asked to more people, had more like a 50% aggregate probability for 50 years away, per Figure 1. [1] “High-level machine intelligence” (HLMI) is achieved when unaided machines can accomplish every task better and more cheaply than human workers.