This number keeps going up, I can't help but notice.
The proliferation of mobile computing devices, wireless and cellular Internet connections, and an always-on culture have led to an upsurge in usage of mobile devices in unexpected and possibly unusual settings for many different tasks. As technology becomes adopted, it is important to examine how it is used and people’s reactions toward these unusual uses. This will help in understanding and describing the expected etiquette surrounding the technology’s usage. People now often use their mobile computing devices in both public and private restrooms. Through a survey of 204 respondents, we explored the acceptability of those practices and the types of tasks people complete using their mobile devices while in a restroom. We discovered 77% of respondents report using some type of mobile computing in restrooms, both public and private, for activities such as text messaging, web browsing, and email. We also determined that younger, male, and heavy technology users were more likely to use technology within restrooms. We discuss the various uses, social acceptance, and implications for technology design.
I think one obvious implication is a "make it really hard to accidentally take pictures with your mobile device" design remit.