The language was able to thrive because of the unusually high percentage of Deaf islanders and because deafness was a recessive trait, which meant that almost anyone might have both Deaf and hearing siblings. In 1854, when the island's Deaf population peaked, an average of one person in 155 was Deaf, while the United States national average was one in about 5,730. In the town of Chilmark, which had the highest concentration of Deaf people on the island, the average was 1 in 25; at one point, in a section of Chilmark called Squibnocket, as much as 1 in 4 of the population of 60 was Deaf.