"Several years" refers to a period of time that is longer than just a few years, but not necessarily a specific number. It means multiple years, typically more than two or three. Full definition
We've used these buffalo plaid stockings for several years now for our five children. (whitearrowshome.com)
Chances are that any fixed rate mortgages that you signed up for several years ago have become significantly lower. (syndicatemortgages.com)
We have seen a continuing shift over the past several years of elected officials working for the benefit of corporations and special interests, and away from helping the people of our great state. (advocatesaz.org)