Are all data unrestricted and free?

No, all data are not unrestricted and free for use.

The general case is free and open access for data, around 91% of the data are accessible. Once the user is registered, he can, by default, access all data which are under CC-BY 4.0 licence.

The restricted data (9%) are withheld from general circulation and disclosure but access may be obtained on a case-by-case basis through negotiation.