GIPS - No of years asking, present, standard, next

Carson

ok, don't shoot me for asking this.

''If a firm is in existance for say last 15 years and wants to present its GIPS compliant results. How many years it has to start with ?

1) Previous 5 years and then add 1 year each for next 5 years or
2) Previous 10 years ? ''

I am bit confused with the wordings of this standard.