Table:
experiment, and length of gap in years
number of postal codes erased and imputed
percentage of postal codes erased and imputed
rule a applied
rule b applied
perfect matches

number
percent

experiment a

1
1,572,760
90.6
91.6
8.4
77.0

2
151,305
8.7
91.5
8.5
72.1

3
10,815
0.6
75.9
24.1
56.5

4
720
0.0
76.7
23.3
51.7

5
20
0.0
60.0
40.0
35.0

total - experiment a
1,735,620
100.0
91.5
8.5
76.4

experiment b

1
2,830,755
81.6
91.4
8.6
76.8

2
547,870
15.8
91.4
8.6
72.0

3
78,510
2.3
76.1
23.9
56.8

4
10,050
0.3
76.2
23.8
53.5

5
1,090
0.0
58.2
41.8
38.0

6
115
0.0
59.6
40.3
29.8

7
15
0.0
64.3
35.7
35.7

total - experiment b
3,468,405
100.0
91.0
9.0
75.5

For the shown table, how many rows and columns are there? Return the result as JSON in the format {"row_number": "m", "column_number": "n"}, e.g., {"row_number": "12", "column_number": "7"}.

There are 18 rows and 6 columns in the table. So, the final answer is {"row_number": "18", "column_number": "6"}.