Table:
all immigrants
immigrant class

family
economic
refugee

ratio

all industries
1.4
1.4
1.3
1.6

industry group

knowledge-based industries
1.6
1.1
2.0
1.0

engineering and information technology
1.6
1.2
2.2
1.0

retail (grocery) and food services
1.9
1.7
1.9
2.1

taxi, janitorial, landscaping
2.5
2.7
1.8
2.1

lessor of real estate
1.5
1.2
2.2
1.1

Statement: the economic class had the highest relative rates of primary self-employment in engineering and it industries.
Question: which immigrant class has the highest relative rates of primary self-employment in engineering and it industries?
Answer: economic