@indemnifyme - Service workers do play an important role in our economy. I find the quinary sector to be the most interesting though.
Most people discount the purchasing power of people like stay at home moms, and I think this is just sheer folly. Even though stay at home moms don't participate in the economy directly by working, they are still a force to be reckoned with.
My mom was a stay at home mom when I was growing up. Even though she didn't make the money, she sure decided how we were going to spend it. She did all the grocery shopping and took care of major household purchases. She also planned all of our vacations. I think all this stuff definitely has an impact on the economy.