17 years old now in 2022 - what year born?

Today, 8 December 2022 if a person is 17 years old now, what year was he born? See below:

If 17 years old, year of birth is:
2004 or 2005*

*It depends on whether he was born before or after 1 January 2005.

If now 17 years and his year of birth 2004 if he was born after 8 December 2004 until 31 december 2004 inclusively, and his year of birth is 2005 if he was born from 1 January 2005 to 8 December 2005.

Other examples:

If now 4 years, year of birth 2017 or 2018
If now 16 years, year of birth 2005 or 2006
If now 21 years, year of birth 2000 or 2001
If now 79 years, year of birth 1942 or 1943

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