As of April 2017, the global marketing share percentage, in terms of the use of search engines (on desktop), heavily favours Google with over 78%.
Now, in Merkle’s Q3 2017 Digital Marketing Report, they also have a share of 97% for US paid search clicks on mobile.
Google search ad spending growth remained strong in Q3 2017, rising to 24% year over year (Y/Y) in the US, while dipping slightly to 13% growth in the UK. Mobile and Google Shopping continued to drive growth, but desktop spending remained resurgent following a late 2016 change by Google to allow advertisers to segment desktop and tablet search ad bids. – Merkle
As the research shows – mobile has the highest share for US paid search clicks with desktop considerably trailing behind.