Paid search is expected to account for over a fifth (21.9%) of global advertising spend this year, a share which has trebled over the past decade, according to data from WARC. Spend on paid search in WARC's 12 key markets is forecast to top $100bn this year, up 11.0% from an estimated $90.5bn in 2017. Analysis of company reports shows that the four largest providers – Google, Baidu, Yahoo and Microsoft – made a combined $I0Ibn from paid search in 2017. Google dominates the landscape, drawing an estimated $85.8bn in 2017. Google attracts the vast majority of search revenue because it is the dominant player in terms of users. This is particularly true for mobile users, with 89.3% preferring Google's search service in April. Smartphones are driving voice search, with data showing that 47% of users utilise voice tech at least once a month on a global level. This share rises to 69% in the US.