In the USA and Europe, Google absolutely dominates the search engine market with the likes of Yahoo and Bing left to play mere bit parts. From its Mountain View headquarters in California, Google can also lay claim to predominantly being the search market leader in the rest of the world.
There are, however, some exceptions. In China, Baidu is the undisputed number one. In 2010, Google withdrew from the country due to censorship issues and has since then had no access to one of the largest advertising markets in the world. According to a forecast from the Statista Digital Market Outlook, 26.5 percent of all search engine advertising revenue is generated in China. That adds up to more than 24 billion US dollars.
You will find more statistics at Statista