The chart above shows the number of certificates of correction issued by the USPTO each year with a forecast through the end of 2015. After a patent issues, a patentee can petition for a correction of “clerical or typographical nature, or of minor character” or mistake by the USPTO. There is no fee if the error is a USPTO mistake and currently a $100 fee for correcting applicant-mistakes.
The number of corrections has remained relatively steady over the past 15 years. Since the number of patents issued has risen so dramatically, this steady-state of correction filings means that the average number of corrections per recently issued patent has dropped significantly since 2001.