What industry is more attrition prone?

Well, I always thought that IT industry is the one where attrition is highest. With people saying "Wow! I really spent long time here, I need some change". This is after just 3 years. But I now found more volatile industry - real estate. I have just purchased a new house. For last two years I have been visiting the construction site, I found every six months there is a new person working as site engineer. This one beats IT with large margine 6 months to 3 years. Not sure of attrition rate of Indian BPO industries, but there is fair chance that it will BPO too.