Python 1.6, 2.7.17, and 3.8, 39 bytes##bytes

The (currently) latest versions of each major release.

print(2000+(str(2>1)!='1')*round(39/2))

Try them online!

Here, I'll evaluate them until the most important parts.

Python 1.6:

print(2000+('1'!='1')*round(39/2))

Python 2.7.17:

print(2000+True*round(19))

Python 3.8

print(2000+True*round(19.5))