Experience value close to 2000 and negative for certain cases.

[lakshmanaram]

For some rare resume, experience value is calculated to be close to 2000 or negative.

[lakshmanaram]

In cvscan/details_parser.py

return end_year - start_year

end_year can be 2015 and start_year can be recognised as 14, in which case the experience is 2001, etc.
In some cases end_year < start_year, regex should be corrected.