U.S. Trade Representative Jamieson Greer talks with Mexican Economy Minister Marcelo Ebrard as they leave National Palace amid talks to review the U.S.-Mexico-Canada trade pact, in Mexico City last month. | REUTERS WASHINGTON/MEXICO CITY – U.S. President Donald Trump’s administration issued a sweeping demand to Mexico to raise the level of regional content in North American-built cars and trucks to 82% to qualify for preferential trade deal access, with 50% of that value produced in the United States, four people familiar with the U.S. negotiating stance said on Friday. The proposed new thresholds were revealed to automakers during two days of bilateral talks to revise the U.S.-Mexico-Canada Agreement on trade that concluded on Friday. Canada was excluded from the negotiations in Mexico City. There was no provision for counting any parts content from Canada in the revised totals.…