The National Safety Council reports the following age breakdown for licensed drivers in the United States.

Age (Years)                            Licensed Drivers (Millions)
under.........................................................................20 9.50
20–under 25.................................................................16.50
25–under 35................................................................ 34.02
35–under 45................................................................ 40.88
45–under 55................................................................ 40.74
55–under 65................................................................ 26.17
65 or over..................................................................... 28.90

Identify the following for the 35–under 45 class:
(a) Frequency, 

(b) Upper and lower limits, 

(c) Width,

(d) Midpoint.