BATTLE GROUND — Compared with juggling four kids younger than 14, asking for a raise should have been easy, thought Chris Waller.Waller, 38, works for a family company that fits expensive products into safe packaging, such as computer chips into tailored foam cases. He earned $14 per hour to start. More than six years later, he was making only $15.70.With costs rising, he asked a supervisor about a raise. But he was rebuffed again and again until, finally, he gave two weeks’ notice.“I was asking for (a raise for) eight months and kept getting the runaround,” he said. “I work hard.”Despite a growing demand for workers, stagnant wages have been a common plight for people like Waller who earn less than $48,000, the Clark County median annual wage. Incomes rose only 6 percent on average for those workers in the past decade, according to state data.By contrast, people whose income ranks in the top 20th percentile saw their paychecks grow 14 percent. The top 5 percent of local earners averaged raises of 20 percent.It’s a global trend that is largely out of the hands of local governments and businesses. But many in Clark County still risk being left out of economic growth.