The table below will be used for the following five questions. The table represents the mean and standard deviation graduation rates, by candidate age, for a population of flight academies.

Age	Mean Graduation Rate	Standard Deviation
16	76.6	1.8
17	74.2	1.8
18	79.5	1.7
19	79.6	2.1
20	81.2	2.1
21	84.2	2.2
22	85.5	2.1
23	88.5	1.4
24	86.5	1.5
25	87.7	1.9
26	87.8	1.5
27	88.1	1.6
28	89.8	1.8
29	90.1	1.8
30	87.8	2.3
31	88.3	2.2
32	88.3	1.7
33	84.5	1.9
34	85.1	1.6
35	88.1	1.4
36	88.2	1.5
37	86.5	1.4
38	84.5	1.8
39	88.8	1.9
40	84.4	1.6

1. A flight academy has a graduation rate of 83.5 among all their 28-year old candidates from the last eight years. What percentage of flight academies have a lower graduation rate for 28-year old candidates?