Dense and sparse partition by local density in five text corpora: observed proportions (10.0–10.5% and 90.0–90.5%)

In five text corpora (Forums, Newsgroups, UFO, eBird Checklist, and eBird Species), totaling 516,556 documents, each document was represented in a 100-dimensional space and assigned a local density value based on nearest neighbors. Using a fixed threshold per corpus, documents were split into two groups: dense (high local density) and sparse (the remainder). The fraction of documents classified as dense lies between 10.0% and 10.5% in every corpus, while the fraction classified as sparse lies between 90.0% and 90.5%. The five corpora differ in size (from 17,242 to 217,587 documents) and domain. The observation is documented in data/observation_table.csv; the table and the proportions figure can be reproduced from the JSON files in data/ using code/reproduce_observation.py. This report is limited to documenting these proportions and does not interpret causes or generality.