The usual way to refer to years is to pronounce the first two digits
together as one number, and the second two together as another number.
The year 2020 will be "twenty-twenty," and the year 2115 will
There are other styles you might sometimes hear. Radio announcers,
for example, like to add a certain style to their deliveries by pronouncing
the numbers of time and date in flowery, almost poetic ways. Thus, you
might hear: "Two-thousand and twenty," or "Two-oh-two-oh,"
and "Two-thousand-and-fifteen," "two-thousand-fifteen,"
or "two-thousand-one-hundred-and-fifteen." Business people
would shorten the form to "twenty" and to "fifteen."
The year 2001 is regularly pronounced as "two-thousand-one,"
or in a short form, "oh-one" (for '01).