Not to derail the importance of your focus - that isn't my intention - I feel it's important to note that amongst slaves in the world today are prisoners held directly by governments, or private corporations on behalf of governments.
There are several million Americans today held by local, regional, state, and federal penal systems, and all of them are slaves. I don't know if the graphic above includes these slaves, but it doesn't mention prisoners, unless under the heading 'factory and farm slavery'.
There are more slaves in America today than ever before.
Keep up the good fight.
Thanks!