US unemployment data release date

Using the CSV file provided by St. Louis Fed (which is based on the data series LNS14000000 from the Bureau of Labor Statistics) I noticed that the date is always the first day of each month for the unemployment rate, i.e. for May 1957 it is 1957-05-01 and so on. Because BLS currently will announce the data for June 2018 on the 6th of July, I doubt that the CSV file is correct. Where can I find the accurate historic release dates for the unemployment rates?