Must adsense format be like : pub-xxxxxxxxxxxxxxxx ?

Must adsense format be like this pub-xxxxxxxxxxxxxxxx ?

Or it can be like this ca-pub-xxxxxxxxxxxxxxxx too ?

Thanks

 

Yes, you can check it out from adsense panel "my account"

 

I do check it from there. But on DP , ad revenue sharing place, http://forums.digitalpoint.com/profile.php?do=editoptions :

If you have an AdSense account, you can enter your client ID here. You then have a 50% chance that the AdSense ads displayed are credited to your account on threads you participate in.
It should be in the form of pub-xxxxxxxxxxxxxxxx

That is why I asked

 

my is ca-pub-xxxxxxxxxxxxxxxx
but I live in USA

ca = Canada?