(Adds polling and context) MEXICO CITY, Aug 25 (Reuters) - Mexico’s economy grew 1.5% in the second quarter from the previous three-month period and registered a double-digit rebound over the same period last year, when most businesses were closed during the first pandemic-related shutdown. Both numbers were close to a preliminary reading of the quarter in July, but came in slightly below a forecast of analysts polled by Reuters. In annual terms, the economy expanded 19.6% compared to a year earlier, the national statistics agency said on Wednesday. Private economist polled by the Central Bank in August raised their 2021 growth forecast for Mexico’s economy to 6.1%. (Reporting by Marion Giraldo in Santiago and Miguel Angel Gutierrez in Mexico City; Writing by Frank Jack Daniel; Editing by Bernadette Baum) Our Standards: The Thomson Reuters Trust Principles.