Spending on advertising in the United States is expected to increase at an annual average rate of 3.3 percent through 2019, a new study estimates. Advertising contributed $3.4 trillion to the U.S. gross domestic product in 2014, or 19 percent of the nation’s total economic output, according to the report commissioned by the Association of National Advertisers and The Advertising Coalition. The research by IHS Economics and Country Risk provides a comprehensive assessment of the contribution of advertising to national, state and regional economic activity across 17 industries. Advertising spending in Iowa last year was $3.2 billion, or 16.1 percent of state output. The study found that U.S. advertising expenditures generated $5.8 trillion in overall consumer sales, including direct, indirect and induced expenditures, representing 16 percent of all sales activity in the United States.