JHK photometry of young clusters near the Sun

We find 143 surveys from 69 published articles, covering 73 different regions. The number distribution of stars in a region has a median of 28 and a mean of 100.

About 80% of the stars are in clusters with at least 100 members. By a rough classification of the groups and clusters based on the number of their associated stars, we show that most of the stars form in large clusters. The spatial distribution of catalogued regions in the Galactic plane shows a relative lack of observed stellar groups and clusters in the range 270{deg}<l<60{deg} of Galactic longitude, reflecting our location between the Local and Sagittarius arms.