BUENOS AIRES, Jan 4 (Reuters) - Argentina collected 679 billion pesos ($8 billion) in tax revenue in December, up 38.6% versus the same month a year earlier, the government’s AFIP tax authority said on Monday. Revenue was up 32.1% in 2020 compared to the previous year, it added. (Reporting by Lucia Sigal, writing by Aislinn Laing, editing by Chris Reese)