The Yale Budget Lab noted that the letters sent Monday would hike the effective tariff rate on U.S. consumers to the highest since 1934.

President Donald Trump said he will announce a 50% tariff on imported copper on Tuesday, an effort to boost U.S. production of a metal critical to electric vehicles, military hardware, the power grid and many consumer goods.

President Donald Trump has sent letters to 14 countries outlining higher tariffs they’ll face if they don’t make trade deals with the U.S. by Aug. 1.