Spanish newspaper, El País published a recent article about the 2019 Chilean Protests:
La manifestación más grande de Chile desde que cayó en 1990 el dictador Augusto Pinochet reunió este viernes en Santiago de Chile a al menos un millón de personas cuando se cumple una semana de las protestas contra la desigualdad social en el país y que ya deja 19 muertos, al menos 600 heridos y 6.000 detenidos, según la Fiscalía.
Google Translate:
The largest demonstration in Chile since the fall of the dictator Augusto Pinochet in 1990 brought together at least one million people this Friday in Santiago de Chile when a week of protests against social inequality in the country is over and that already leaves 19 dead At least 600 injured and 6,000 arrested, according to the Prosecutor's Office.
That would suggest the equivalent of over 5% of Chile's 18 million population were present.
Was this estimate accurate?