The Pew Research Center has released a study with some interesting results. Tablet ownership has increased from 11% of adults in July 2011 to 22% now. While Apple had a huge head start their share of the growing market is dropping rapidly from 81% of the market to 52%.
This trend will affect construction iPad and real estate iPad usage. It will be more cost effective to issue Android tablets to employees than iPads. This reduces the cost of replacement as well if they get lost or damaged. While the iPad is still dominant you should keep an eye on alternatives as their quality is improving rapidly.