ENUMs scare me because of any issue regarding adding/removing type values. You are probably better off representing both ProfessionalType and Decile as TINYINT or CHAR(3). Anything but ENUM.
See my past posts on ENUM :
Ocy 19, 2011: Advantages and Disadvantages to using ENUM vs Integer types?Advantages and Disadvantages to using ENUM vs Integer types?Jan 24, 2012: Is it possible to change ENUM() lists?Is it possible to change ENUM() lists?
For efficiency, please do not index this field alone, given such a low cardinality (8,10).
