Two years after Microsoft CEO Satya Nadella cut the cord between his firm's biggest money makers -- Office and Windows -- by introducing mobile productivity apps for Apple's iPhones and iPads, the Redmond, Wash. company remains far behind rival Google in the category, a researcher said today.

According to data provided to Computerworld by SurveyMonkey Intelligence, the monthly-active users of Google's mobile productivity apps in April vastly outnumbered those for Microsoft's Office.

"I was surprised that Google was dominating as much as it is," said Bonnie Yu, a product manager at SurveyMonkey. "I really expected Microsoft to be a better competitor."

SurveyMonkey is an online survey firm whose customers use the platform to craft customized surveys. Yu works with SurveyMonkey Intelligence, an arm that mines data from those surveys to provide information to clients on topics like device and software usage, market research and demographics.

Yu had pulled data for Computerworld on U.S. usage of Google's and Microsoft's productivity apps on mobile devices, expressed as monthly-active users, or the number who ran each app at least once in April.

The results, as Yu noted, were startling.

Microsoft's core Office apps -- Excel and Word -- badly trailed their rivals from Google, Sheets and Docs, respectively.

Google Sheets boasted 2.9 million monthly-active users in April, more than double the 1.4 million who ran the Excel app. Meanwhile, Google Docs monthly-active users outnumbered Word by more than five to one: 24.6 million for Docs, 4.6 million for Word.

Other app categories were just as unbalanced. Gmail, for example, was used by 96.7 million people last month, while Microsoft's Outlook app -- praised by many reviewers -- sported just 6.3 million. In online storage, Google Drive bagged nearly 10 times the number of monthly-active users than did Microsoft's OneDrive: 47 million to 4.9 million.

Microsoft introduced its first mobile apps for Office in March 2014, when Nadella unveiled Office for iPad, breaking with his firm's past practice of protecting Windows by first launching software on its own operating system.

Since then, Microsoft has rolled out mobile Office apps for Android and fleshed out its portfolio with Outlook and OneDrive apps for both iOS and Android.

Microsoft's own mobile platform -- Windows Phone and its successor, Windows 10 Mobile -- have a tiny slice of the market, one of the main reasons why the company has turned to the dominant Android and iOS operating systems to extend Office into non-PC devices.

In fact, pushing Office at Android and iOS users has been a key component of Microsoft's "cloud first, mobile first" strategy. Using a "freemium" business model -- the term used for free apps that generate revenue by in-app purchases -- Microsoft aimed to steer customers to Office 365, a subscription service for both consumers and businesses.

Microsoft has been beefing up the Outlook app with acquisitions of small development firms, including Acompli in December 2014 for a reported $200 million and Sunrise Atelier in February 2015 for $100 million. Acompli made an email-organizing app, and Sunrise a calendar app that Microsoft has since announced it will stop selling.

But although the Office mobile apps have generally collected accolades from reviewers and users, SurveyMonkey Intelligence's data signals that Microsoft's apps are used by far fewer customers than are the Google alternatives.

Microsoft has regularly trumpeted the number of Office app downloads as a sign that they have been successful. During a January earnings call with Wall Street, for instance, Nadella said that total Office app downloads had surpassed 340 million in the last three months of 2015, and claimed that there were 30 million active devices running the Outlook app.

Nadella's numbers were global, not U.S.-only, as were SurveyMonkey's, but the disparity between Microsoft's claims and SurveyMonkey's data was striking nonetheless.

"Downloads don't translate to usage," Yu said when asked about the difference. "A lot of apps gets millions of downloads, but not millions and millions of active users."