The mystery of the missing super-Earths and mini-Neptunes may finally be solved

The article stated, "Over the years, scientists have managed to observe many exoplanets that are either smaller or larger than Earth, but planets precisely between 1.6 and 2.2 times the size of our world are relatively scarce."

This site shows 5624 confirmed exoplanets now,

Using SQL query I found 719 fall into the 1.6 up to 2.2 earth radii size. 55 Cnc shows up along with many others and at the end, Wolf 503. The NASA archive site shows 5573 confirmed,

782 show radii 1.6 to 2.2 earth size. 55 Cnc e and Wolf 503 b at start and end of the query list. Migration scenarios to explain various exoplanet observations is intriguing, especially with the population documented today for exoplanets.