Original sentence: Dictionaries when the name was chosen, and through the 1960s and 1970s defined the term as simply: a North American Indian, but by the early 1990s had added the current negative connotations
Edited sentence: Dictionaries when the name was chosen, and through the 1960s and 1970s defined the term as simply: a North American Indian, but by the early 1990s had added a negative connotation