Despite the mounting pressures on Americans of all ages to save for retirement, our saving habits haven’t changed in 10 years. The combined employer and employee contributions to 401(k)s consistently hover around 10 percent of workers’ pay, according to “How America Saves 2018,” an annual report by Vanguard, which administers thousands of employer 401(k)s and other defined contribution plans. Retirement account balances aren’t going up either. The typical participant’s 401(k) balance is no larger than it was in 2007, even though accounts grew 7 percent last year, to $26,000, thanks to a strong stock market. The balances, when adjusted for inflation, are slightly smaller. The growing adoption of 401(k) plans that automatically enroll their workers is having both negative and…