The next time you shop for groceries, pick up something at Walmart or grab lunch at almost any Tri-Cities fast-food restaurant, count the number of workers who are in the 50-plus years old category. That’s right. There’s a lot of them. And their ranks are increasing. An analysis of U.S. Labor Department data by Liscio, a research publication for investors, said Americans 55 and over made up about half of all employment gains in 2018.