As Markerinbound wrote, we are a level 4 by default, as per the FAA directive. It gets even more fun. If you look at your license, the "English Proficient" is not under "ratings", it is under "limitations". That means to some countries that your "english proficient" is a limitation, which means you suck at english!!!! No kidding.
Why, the wise-man asks? You really want the answer? The FAA bought a software package to make new licenses. When they tried to put "english proficient" on the licenses, the software would only allow them to put it under "limitations".
An even better question? Why do I know this? I had to learn it to get a job. English proficient means level 4, which most countries hiring expats now know. It is in the limitations section because the software will only allow them to do it that way.
Even more surprising? I know all this because the FAA guys doing licensing and such are extremely professional, knowledgeable, and helpful. I can't say enough good things about them.
If you are having a problem with a job, give-em a call. You will be surprised at how helpful they are.