A mix of free and low-cost patent statistics by calendar year (Jan. 1 - Dec. 31) available from the Patent Technology Monitoring Team (PTMT) of the USPTO.
The new Open Data Portal (ODP) is launching soon, informed by the Developer Hub (Open Data Portal beta) and real customer feedback. The first iteration will include patent data and improved functionality previously found on Patent Examination Data System (PEDS).
Learn more about the new Open Data Portal in this PDF.
You can still access Developer Hub datasets on https://developer.uspto.gov/data.