I have divided the reputation of a country by 60 and the youth ratings look more realistic now.
It is shown on the screenshots below.
Youth rating = jeugdwaardering on the screenshots
Step 1Move the .fmf file to your editor data folder:
Documents > Sports Interactive > Football Manager 2015 > editor data
Important: Create the "editor data" folder if it doesn't exist.
Notice: There may be two "Sports Interactive" folders in your Documents library. If this is the case then put it in the one which has your saved games inside.
Step 2Start a new career game (won't work with classic mode).
A little pop-up window will come up that says there is X enabled editor files. Select "Custom" from the editor data drop down menu and choose the databases you wish to load in your new save.