A new study of voice recognition assistants on smartphones shows Apple's Siri to be in the lead of all other comers — but usage industry-wide appears to be dropping.

According to a new study by Verto Analytics, 44 percent of all smartphones in the U.S. have a personal assistant app. Siri has 41.4 million users per month of a total pool of users in the U.S. is 71 million.

Siri has nearly twice the user base as its nearest competitor, Samsung S Voice.

Overall, the time spent per user per month has dropped notably in a year, down across the board from 26 minutes to 12.

However, Siri's metrics are falling. Between May 2016 and May 2017, Verto claims that Siri lost 7.3 million monthly users. Samsung S Voice has dropped proportionately as well, suggesting that the decline is more from usability concerns and market trends than any specific concern about Apple's technologies.

Verto postulates that the drop in numbers is from standalone devices, like the Amazon Echo and Google Home series of products, which have seen unspecified "dramatic growth" in the last year. Apple will be joining that market with the HomePod, but with it launching with a subset of Siri specializing in music playback, it will most likely not be considered a standalone voice recognition assistant.