Table:
highest certificate, diploma or degree
female lone parents
female parent in couples

1991
2001
2011
difference
1991
2001
2011
difference

percent

total
100
100
100
..
100
100
100
..

no certificate, diploma or degree
34
20
13
-21
24
13
8
-16

high school diploma or equivalency
30
28
25
-5
32
28
21
-11

postsecondary certificate below the bachelor's level
26
39
42
16
29
36
38
9

university degree at the bachelor's level or above
9
13
20
11
15
23
33
18

Retrieve the content of the cell located in the 8th row and the 4th column of this table. Provide the value of target cell in the JSON structure, using the format {"row_id":"m", "column_id":"n", "cell_value":"<Corresponding Cell Value>"}.

The target cell value in the 8th row and the 4th column is {"row_id":"8", "column_id":"4", "cell_value":"20"}.