Slavery in human society has been ubiquitous. Decoders for features of slavery are encoded in natural language on the legal structures of time based states and nations. Slavery can be encapsulated by state or nation with a timestamp. This gives a pair of symbol, time; where symbol is the address, in a range for the timestamp(s). 

In contemporary nations we may find for example that New York at admission to the nation of the United States of America in 1788 had 0% slaves. Data is generally accepted records and information (accepted by population of the state ~ CE2020) 

In the non-human population, slavery is the rule, wherein for the larger population the terminal result is that the slave is eaten.