Class proportions by age using uniform 1 Myr bins for sources in the PARSEC age range of 0-10 Myr. The orange line (Class I + Flat) shows consistently low values due to the scarcity of these evolutionary stages in the dataset. Uniform bins were used for consistency and ease of comparison across the age range. The fractions were calculated as the number of sources in each class divided by the total number of sources in the respective age bin.