What was the global and national status of slavery during the late 1700s and early 1800s?

In the late 1700s and early 1800s, slavery ended in many countries around the world including Great Britain, although it continued to exist in smaller territories such as Brazil and Puerto Rico. In the United States, most of the northern states outlawed slavery in their own states, although some of them limited this abolition of slavery to slaves born after a certain date.