According to a new report from market research firm eMarketer, an increasing number of users of mobile devices are now using apps on their devices to carry out Internet searches; thereby resulting in a notable plunge in ad revenue for bigwig search engines like Google, Yahoo, and Bing.

Going by the figures shared by eMarketer in its recently-released report, Google's mobile ads revenue has dramatically declined 17 percent since 2012. While Google had a whopping 82.8 percent share of the $2.24 billion search market just two years back, the company's share in mobile search spending has plunged to merely 65.7 percent this year.

The drop in Google's share in mobile search spending is somewhat disquieting, especially given the fact that the revenue recorded by the US mobile ad market touched a staggering $17.73 billion this year; with mobile search spending having leaped to $9.02 billion.

Despite the fact that Google still continues to dominate browser-based searches on mobile devices, the eMarketer reported has highlighted that the usage of niche search apps is becoming more common, and these apps are clearly taking away an incremental market share from Google and other search providers.

With regard to the evident explosion of mobile app development and usage, Cathy Boyle - eMarketer's senior analyst for mobile - said: "Even though browser-based search is a common behavior among mobile owners, search engines are not necessarily the first place smartphone and tablet users turn."