What is a question about this article? If the question is unanswerable, say "unanswerable".

For decades, the U.S. federal government strenuously tried to force Puerto Ricans to adopt English, to the extent of making them use English as the primary language of instruction in their high schools. It was completely unsuccessful, and retreated from that policy in 1948. Puerto Rico was able to maintain its Spanish language, culture, and identity because the relatively small, densely populated island was already home to nearly a million people at the time of the U.S. takeover, all of those spoke Spanish, and the territory was never hit with a massive influx of millions of English speakers like the vast territory acquired from Mexico 50 years earlier.

When did the U.S. government retreat from the policy of making Puerto Ricans use Spanish?
unanswerable