80 years old now in 2023 - what year born?

Today, 22 March 2023 if a person is 80 years old now, what year was he born? See below:

If 80 years old, year of birth is:
1942 or 1943*

*It depends on whether he was born before or after 1 January 1943.

If now 80 years and his year of birth 1942 if he was born after 22 March 1942 until 31 december 1942 inclusively, and his year of birth is 1943 if he was born from 1 January 1943 to 22 March 1943.

Other examples:

If now 8 years, year of birth 2014 or 2015
If now 13 years, year of birth 2009 or 2010
If now 18 years, year of birth 2004 or 2005
If now 49 years, year of birth 1973 or 1974

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