Text messaging among U.S. adults has leveled off, according to a study.

In 2011, American adults sent or received an average of 41.5 text messages a day, about the same number they sent or received in 2010, according to a new report from the Pew Internet and American Life Project. The report is titled, Americans and Text Messaging.

The study also showed that the number of calls made by adults on mobile phones has remained about the same in the past year, as the average adult mobile phone owner made or received an average of 12 calls per day.

But the study's author says we shouldn't conclude that the mobile phone market is saturated from the findings.

Partially it's that people have reached a natural plateau in terms of how much they're willing to text, said the study's author Aaron Smith. I think more to the point there's a natural level at which people like to text and over the course of a year or so that may not change that much, but I think if you were to measure this over several years you might see a bit more of a difference.

Another likely reason for the leveling off of text messaging and mobile phone calling among adults is that more are using social media through Facebook, Google+, LinkedIn and other sources to connect with friends and colleagues. They're also using different devices, including tablets like the Apple iPad instead of mobile phones to connect.

The study found that most adults who own mobile phones do use text messaging, however. The study also found that adults who qualified as heavy text message users -- with 50 or more texts sent or received each day -- prefer texting to speaking on the phone.

The study found that young adults -- those aged 18 to 24 -- are the most frequent texters, sending or receiving an average of 109.5 messages per day.

The survey was conducted by phone and included 2,277 respondents over the age of 18, according to the Pew Internet and American Life Project. The study was conducted from April-May 2011.