Rankings count each patent once by its primary Cooperative Patent Classification. All-time pages aggregate the full database; year pages use patent grant year.
Recent years: 2016201720182019202020212022202320242025
Primary CPC class A21 · Section A
Rankings count each patent once by its primary Cooperative Patent Classification. All-time pages aggregate the full database; year pages use patent grant year.
Recent years: 2016201720182019202020212022202320242025