Table:
period

1981 to 2000
2000 to 2008
1981 to 2009

percent

value-added growth (log), annual average
3.22
0.39
2.31

percentage points

contribution

labour input
0.08
0.84
0.32

produced capital input
2.45
4.64
3.16

natural capital input
0.43
0.16
0.34

multifactor productiivty
0.26
-5.25
-1.51

percent

multifactor productivity growth (log), annual average before adding natural capital
-0.04
-6.96
-2.27

The task is as follows:
Analyze the table in this image to find every merged cell. Return the regions of these merged cells in the JSON {'top-left':(x, y), 'bottom-right':(m, n)}, where '(x, y)' and '(m, n)' show the (row_id, column_id) of the top-left and bottom-right cells in these regions, respectively. The row and column IDs start from 1.

The merged cell regions are as follows:
{'top-left':(1, 1), 'bottom-right':(3, 1)}
{'top-left':(1, 2), 'bottom-right':(1, 4)}
{'top-left':(3, 2), 'bottom-right':(3, 4)}
{'top-left':(5, 2), 'bottom-right':(5, 4)}
{'top-left':(6, 2), 'bottom-right':(6, 4)}
{'top-left':(11, 2), 'bottom-right':(11, 4)}.