The stacked bar chart (blue & yellow) uses the left-side axis. The deltas (Δ) represent the absolute difference in files for Commons (Δ in the blue bars) and for all other wikis (Δ in the yellow bars) between the start and end dates of the chart. The standalone Δ_total is the total difference for all wikis combined. The top (green) line chart uses the right-side axis.

The data was edited to compensate for the following issues:

• Files with missing machine-readable metadata were overcounted between 2014-10-10 and 2014-10-30. Data was edited to provide a consistent transition between before and after the bug was fixed.
• Data for Commons wasn't recorded prior to 2014-12-11. Data was backfilled using the data at that date. Rationale: There were no major efforts to fix files on Commons before that date, and new uploads include machine-readable templates. This means we can reasonably assume that the number of files missing machine-readable metadata on Commons remained fairly constant during this period.
• Total tallies were similarly backfilled to add the Commons total prior to 2014-12-11.
• Data for Commons wasn't recorded on 2014-12-14, 2015-01-15 and 2015-01-16. Data was backfilled using the last available data.