Nate Silver explains how he was able to come up with these statistics:
In regards to the Magic, you can see that its racial distribution is very similar to the overall average NBA fan distribution. Orlando has the 15th-highest distribution of Whites (45.6%) among the thirty franchises. The 11th-most distribution of Blacks (34.4%). The Magic rank 12th in distribution of Hispanics (15.5%). As well as being #21 in distribution of Asians (4.6%).