This file defines how many proficiencies * a character will have at his/her creation, and how often he/she will get an other one.
First column is the list of classes identifiers.
2nd column is just the number of proficiency * given at the PC creation from the class defined in column 1st.
3rd column is the levels number that should be obtained to receive another proficiency *. A value of 0 causes a crash during character generation.
In BG1 TotS we have:

2DA V1.0
0
           		FIRST_LEVEL RATE       
MAGE       		1           6
FIGHTER    		4           3
CLERIC     		2           4
THIEF      		2           4
BARD       		2           4
PALADIN    		4           3
DRUID      		2           4
RANGER     		4           3
FIGHTER_MAGE 		4           3
FIGHTER_CLERIC 		4           3
FIGHTER_THIEF 		4           3
FIGHTER_MAGE_THIEF 	4           3
MAGE_THIEF 		2           4
CLERIC_MAGE 		2           4
CLERIC_THIEF 		2           4
FIGHTER_DRUID 		4           3
FIGHTER_MAGE_CLERIC 	4           3
CLERIC_RANGER 		4           3