Definition
This measure counts listed WordPress plugins in each active-install bucket that WordPress.org itself reports on plugin listings. It shows how the whole directory is spread across install-size groups. The groups run from the smallest bucket WordPress.org publishes up to the largest. Every listed plugin falls into exactly one bucket at the stated date.
Population and window
Rivale measures this across the whole directory, meaning every plugin listed on WordPress.org on the issue's data date. The window is a single date, the last day of the report month. The figure describes one date, not a monthly total. The same bucket definitions are used in every issue.
How it is computed
A count of listed plugins in each bucket published by WordPress.org, from under 1,000 to 1M or more. Bucket edges are set by WordPress.org, not by Rivale.
How to read it
Install counts are bucketed by WordPress.org, with the bucket edges set by WordPress.org rather than chosen by Rivale. A plugin is placed inside a bucket, not given an exact install count in this measure. Read it beside top-3 install share to see how installs concentrate within a single tag. Compare it across issues to see how the directory's overall install-size mix shifts over time. A directory weighted toward the smallest buckets says most listed plugins carry few active installs, not that the directory is shrinking.
What it is not
This measure does not give an exact install count for any plugin. The bucket edges are not a choice Rivale makes, but one set by WordPress.org's own reporting. It does not track how a plugin moved between buckets over time in a single figure. It is not limited to the top 12,500 plugins, unlike several other measures in this dictionary. It is not a measure of downloads or of any plugin's own popularity rank.