Population studies of exoplanets are key to unlocking their statistical properties. So far, the inferred properties have been mostly limited to planetary, orbital, and stellar parameters extracted from, e.g., Kepler, radial velocity, and Gaia data. More recently an increasing number of exoplanet atmospheres have been observed in detail from space and the ground. Generally, however, these atmospheric studies have focused on individual planets, with the exception of a couple of works that have detected the presence of water vapor and clouds in populations of gaseous planets via transmission spectroscopy.
Here, I will present a recent effort to understand the population of observed exoplanets via the study of their atmospheric properties. The work involves 70+ exoplanets observed in transit and eclipse spectroscopy by the Hubble Space Telescopes.