I read in another forum post that PI chips often use date codes in the form A000, where the initial letter indicates manufacturing location, and the second character (first digit) tells the year, and the final two digits tell the week.

But how does that one year digit distinguish between 2000's, 2010's and 2020's?  For example, I have a batch of TOP232P ICs marked "K034". Were they made in 2010 or 2020?

Thanks!