Google is the leader in Search Engines and Google is the most used search engine in the world besides Bing, Yahoo and DuckDuckgo.
The percentage of the search market for Google Search is 92.37% and for Yahoo it's 2.25% and Bing gets 2.37% of the search market.
While Google Search is the most widely used search engine A lot of people do search for things on Yahoo and Bing and I do get a lot of website traffic coming to my website through searches from Yahoo and Bing.
So if you're running a website don't think that Google has to bring in all your search traffic since Yahoo and Bing can also bring in search traffic.
I've ranked content on Bing and Yahoo search within 1 day while on Google that same content took 6 months to rank.