What was the ratio of black slaves to white people in Charleston SC in 1865?

In 1865, Charleston, South Carolina, had a significantly higher population of black slaves compared to white residents. It is estimated that there were approximately 40,000 black slaves to around 10,000 white people, resulting in a ratio of about 4:1. This demographic imbalance was largely due to the city's role as a major center of the slave trade and plantation economy in the antebellum South.