Mozilla's decision to part ways with Google as the default search provider in Firefox, which went into effect at the beginning of December, is already having a pretty significant impact on the US-based Internet search market.

Data from web analytics firm StatCounter shows that Google's share of the search market in the US fell 2.1 percent at the end of 2014, from 77.3 percent in November to 75.2 percent in December. Yahoo's share, meanwhile, increased 1.8 percent - from 8.6 percent in November to 10.4 percent a month later.

Those few percentage points may not sound like much but it's pretty significant. For Google, it's the lowest US share yet recorded by StatCounter which began recording statistics in 2008. And for the Marissa Mayer-led Yahoo, it's the highest US search share the company has enjoyed since 2009.

The shift in market share is a direct result of the five-year deal that Mozilla signed with Yahoo late last year to become the default search provider in Firefox 34. For the past 10 years, Mozilla had relied on Google to provide the default search experience in its web browser.

As of December, Firefox held just over 12 percent of the browser market in the US according to StatCounter.

It's also worth mentioning that Apple's agreement with Google to be the default search provider in Safari expires this year. Things could get even more interesting should Google lose out on this deal, especially if Yahoo is able to land it.