When you click in a date entry field the calendar pops up for you to select your date. The current month is displayed and clicking the arrows next to the name of the month allows you to move one month either way.
Click once on the month at the top of the calendar pop-up. This changes to years so you can scroll by year, and the main panel now shows months.
Click at the top of the pop-up again and years changes to decades.
Click the required year, then month then select the day to return a value to the date field.
Alternative, if you have are using a device with a keyboard, hit the Esc key on your keyboard to clear the pop-up and you can manually enter your date.