Samples by body site.

Each row indicates a body site related to the human microbiome. The “Samples” column indicates the total number of samples categorized under each body site, and the “Countries” column indicates the number of unique countries with at least 1 sample in that category. Samples without a known country are included in the sample count, but not the country count. Body sites map directly to categories defined in the NCBI Taxonomy Browser; see S5 Table for a list of category IDs combined for each body site.