Requests processed per year
The number of certificate requests processed under the scheme each year. Note that the final bar is normally an under-representation since it is based on period-to-date figures.
Certificates in use
The approximate number of un-expired certificates issued under the scheme at any particular time. This gives a further approximation of the number of certificates in use. These numbers are approximate because, amongst other things, they are based on requests for certificates and not all requests are processed, and because not all certificates are used for their full lifetime. Further from April 2014 the numbers fail to allow for approximately 100 certificates that were revoked following the Heartbleed incident.