Table:
sector
import participation rate
export participation rate

all firms
immigrant-owned firms
all firms
immigrant-owned firms

percent

manufacturing
30.64
28.56
20.04
14.76

wholesale trade
31.54
32.88
10.42
10.58

Examine the table in this image and extract any merged cell areas. Please format the merged cell areas as JSON {'top-left':(A, B), 'bottom-right':(C, D)}, with (A, B) indicating the (row_id, column_id) of the top-left cell and (C, D) the bottom-right cell in the merged regions. Remember that the A, B, C, D all start from 1.

The merged cell areas are as follows:
{'top-left':(1, 1), 'bottom-right':(3, 1)}
{'top-left':(1, 2), 'bottom-right':(1, 3)}
{'top-left':(1, 4), 'bottom-right':(1, 5)}
{'top-left':(3, 2), 'bottom-right':(3, 5)}.