Table:
bac
bac

2 years before
2 years after
2012
2016

percent

industrial sector

goods-producing industries
4.7
6.4
10.5
11.1

low value-added service industry
22.1
9.9
11.0
8.3

high value-added service industry
30.2
36.6
39.4
38.3

educational services
9.9
11.6
11.8
12.9

health care and social assistance
12.8
14.0
9.8
9.2

public administration
15.1
18.0
12.0
14.0

unknown
5.2
3.5
5.5
6.1

unionization rate

had union contributions
37.8
42.4
35.9
37.7

had no union contributions
62.2
57.6
64.1
62.3

rate of participation in a pension plan

participated in a pension plan
30.2
46.5
37.0
46.3

did not participate in a pension plan
69.8
53.5
63.0
53.7

Statement: the unionization rate increased by 4.6 percentage points from 37.8% to 42.4% two years before and two years after obtaining the short-duration credential.
Question: what was the unionization rate increased betweeen two years before and two years after obtaining the short-duration credential?
Answer: [4.6]