"born" approximation

The "born" field in a laureate collection document records the date of birth of that laureate. "born" values are of the form "YYYY-MM-DD", also known as ISO 8601 format. An example value is "1937-02-01", for February 1st, 1937. This format is convenient for lexicographic comparison. For example, the query

db.laureates.count_documents({"born": {"$lt": "1900"}})

returns the number of laureates with recorded dates of birth earlier than the year 1900 ("$lt" is for "less than"). Using the query format above, what is the number of laureates born prior to 1800? What about prior to 1700?