And when the scores rise, they’re adjusted to the mean. Because 100 means of average intelligence, and the average intelligence rises, so the average is adjusted for.

https://en.wikipedia.org/wiki/Flynn_effect

Ulric Neisser estimated that using the IQ values of 1997, the average IQ of the United States in 1932, according to the first Stanford–Binet Intelligence Scales standardization sample, was 80. Neisser states that “Hardly any of them would have scored ‘very superior’, but nearly one-quarter would have appeared to be ‘deficient.’” He also wrote that “Test scores are certainly going up all over the world, but whether intelligence itself has risen remains controversial.”