While the severe underrepresentation of women and non-binary people in open source is widely recognized, there is little empirical data on how the situation has changed over time and which subcommunities have been more effectively reducing the gender imbalance. To obtain a clearer image of gender representation in open source, we compiled and synthesized existing empirical data from the literature, and computed historical trends in the representation of women across 20 open source ecosystems. While inherently limited by the ability of automatic name-based gender inference to capture true gender identities at an individual level, our census still provides valuable population-level insights. Across all and in most ecosystems, we observed a promising upward trend in the percentage of women among code contributors over time, but also high variation in the percentage of women contributors across ecosystems. We also found that, in most ecosystems, women withdraw earlier from open-source participation than men. General Abstract-The representation of women and non-binary people has been extremely low in the open-source software community. Most of the statistics reported by prior studies are below 10%. However, the majority of the prior works were based on subsamples instead of the entire population. Our work started with a review of the gender distributions reported in the literature. Then we provided an overview of the gender distribution in 20 of the largest open-source ecosystem, i.e., grouped by package managers such as npm and PyPI, and investigated its change over time. Moreover, we analyzed the turnover rate between men and women contributors. Across all and in most ecosystems, we observed a promising upward trend in the percentage of women among code contributors over time, but also high variation in the percentage of women contributors across ecosystems. We also found that, in most ecosystems, women withdraw earlier from open-source participation than men.
