Countries

Europe was not one big market for Nintendo. Europe was split into different markets.
Every market has its own tag at the end of the license number.

1. Germany
Germany was probably the biggest and most succesful market. Carts released here have the 'NOE' tag. 'NOE' stands for Nintendo of Europe, which is situated in Germany.

2. Austria & Switzerland
Some games are hard to get in PAL-format, and many times the license number of these games ends on 'FRG'. I have some of these games and on the manual and box is always information about distributors from Austria and Switzerland. I believe 'FRG' stands for 'French German'.    

3. France, the Netherlands, Belgium & Luxembourg
These countries have the 'FRA'-tag. However there are a few games with the 'HOL'-tag. Games with this tag are only released in the Netherlands and the Dutch-speaking part of Belgium (Flanders). This is because some games were also released in the French language, and these games carry the 'FRA'-tag. In Holland and the Dutch-speaking part of Belgium the English versions of these games were released, with the 'HOL'-tag. Examples of such games are: Shadowgate, Kirby's Adventure, Duck Tales 2 and Swords and Serpents.

4. Sweden, Norway, Denmark, Finland & Iceland
These are the Scandinavian countries, The NES was also released in Iceland. According to a Swedish magazine, it sold about 60,000 copies. I'm not sure about the figure, though. This magazine was made by the company that sold the NES in Sweden and it was usually filled with lies to make Nintendo or Bergsala (the company) look better. Thanks to Sverker Johansson for this information. NES-games released in Scandinavia have the 'SCN'-tag.

5. United Kingdom & Ireland
NES games from the UK have either the 'GBR' or the 'UKV'-tag. Together with games from Australia and Italy, the games released here are using another PAL-format, NES games from these countries have an 'A' on the label (except games published by Nintendo). Games from all other countries have a 'B' on the label.

6. Spain & Portugal
Same question as before about Portugal here. NES games from Spain have the 'ESP'-tag. And many times the label of a game read 'Spanish version', while the game is just in English.

7. Italy
NES games from Italy have the 'ITA'-tag. I don't own any NES game from Italy.

8. Australia & New Zealand
Although far way from Europe, these countries are also using the PAL format. Just like games from Italy and the UK, have Australian games the letter A on the label. There are some Australian exclusives games, such as Aussie Rules Footy and Championship Rally.