Table:
period
all exporters
small,more than 10but less than 100
medium,100 to 250
large,more than 250

percent

1974 to 1979
27.8
23.6
24.7
28.5

1979 to 1984
31.7
28.3
27.1
32.6

1984 to 1990
36.2
29.1
26.5
38.6

1990 to 1996
42.0
29.6
33.1
45.3

1996 to 2000
46.1
32.4
38.3
49.3

2000 to 2005
45.2
35.9
41.4
47.7

2005 to 2010
41.2
37.4
41.4
42.0

all period
41.4
33.1
37.0
43.4

Different merged cells often exist in a table and they can be represented by the JSON {'top-left':(x, y), 'bottom-right':(m, n)}. In this JSON item, '(x, y)' and '(m, n)' are the (row_id, column_id) coordinates for the top-left and bottom-right cells in the merged region, respectively. Please examine the provided table image, identify all merged cells, and return their details using the above-mentioned format. Remember, the numbering for both rows and columns starts at 1.

The merged cell region is: {'top-left':(2, 2), 'bottom-right':(2, 5)}.