SAN FRANCISCO — An annual Wikipedia fundraising campaign ended Tuesday with donors around the world pumping a record $20 million into the foundation that runs the free online knowledge repository.

Non-profit Wikimedia Foundation launched the campaign in November, getting an early boost in the form of a $500,000 grant from Google co-founder Sergey Brin and his wife.

The total amount of money donated has climbed each year since Wikimedia began the fundraising campaigns in 2003.

"Our model is working fantastically well," said foundation executive director Sue Gardner.

"Ordinary people use Wikipedia and they like it, so they chip in some cash so it will continue to thrive."

Wikimedia reported that more than 470 million people each month use its websites, which are supported by donations and not by advertising. Wikimedia projects include Wiktionary and Wikibooks.

Volunteer-staffed Wikipedia will turn 11 years old on January 15th and boasts being the largest encyclopedia in history with more than 20 million articles in 282 languages.