Retail sales growth in the U.S. is expected to slow down in 2019 amid cooling economic conditions, according to the National Retail Federation, Bloomberg reported. Americans will boost retail spending by 3.8 percent to 4.4 percent this year, the NRF said. For comparison, preliminary estimates show that sales rose 4.6 percent in 2018, according to the group. The NRF used a combination of government data and its own estimates. The forecast comes amid concerns about global economic activity that spans from Europe to China. Although the U.S has largely been anchored by strong consumer spending, NRF President Matt Shay warned that headwinds from the government shutdown and the ongoing trade war could erode Americans’ appetite for shopping.