Related Clues:

• 9 to 5, e.g
• The proportion of numbers the TD exchanges for the radio?
• 10:1, e.g
• "1 inch = 10 miles," e.g
• There's often a colon in one
• It has a colon in the middle
• Tangent, e.g
• See 1
• See 18
• See 11
• See 23
• Supply restricted in proportion
• Separationist has covert relationship
• Say, one to five in operation
• Irrational number in sequence - pi?