Viewership for one big live TV event -- the NCAA Basketball Tournament -- is growing on digital devices, more significantly for Apple iOS mobile platforms than Android.Although Android continues to have a larger market share than iOS -- 51.5% versus 41.8% -- iOS grabbed top honors as the most used operating system for the nearly month-long event in March with a 40.84% share against Android’s 27.23%. This data comes from video delivery company Clearleap based on its internal database and verification services. Clearleap works with 20 to 25 service providers.Mobile viewership also went the way of Apple iOS platforms -- 59.9% of all mobile viewers watch on devices like the iPhone and iPad. Android devices were at 22.8%. Other systems -- Windows Phone and BlackBerry -- had negligible results.Looking at all second screens, phones topped desktop computers and tablets -- getting 43.7% of viewers, versus 31.8% for desktops; and 24.5% for tablets.The traditional TV event on CBS and Turner posted better overall digital results versus a year ago. In the first week of the tournament, there were 51 million video streams, more than the total of 49 million video streams for the entire event a year before.Also, when it came to the championship game, which witnessed a 10% decline in ratings for the Kentucky-Connecticut game, mobile shone. There were 2 million live streams -- up 30% from the championship game a year before.