3 added 145 characters in body
source | link

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is (TableForm'd for clarity)

1   1   2
1   1   2
1   2   3
1   2   3
1   2   3
2   1   2
2   1   2
2   2   3
2   2   3
2   2   3

EDIT Timing-wise, this starts to get increasingly sluggish at ~4,000 records, so the approaches that use ..Array or Dispatch may be preferable.

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is (TableForm'd for clarity)

1   1   2
1   1   2
1   2   3
1   2   3
1   2   3
2   1   2
2   1   2
2   2   3
2   2   3
2   2   3

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is (TableForm'd for clarity)

1   1   2
1   1   2
1   2   3
1   2   3
1   2   3
2   1   2
2   1   2
2   2   3
2   2   3
2   2   3

EDIT Timing-wise, this starts to get increasingly sluggish at ~4,000 records, so the approaches that use ..Array or Dispatch may be preferable.

2 added 27 characters in body
source | link

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is

1 1 2

1 1 2

1 2 3

1 2 3

1 2 3

2 1 2

2 1 2

2 2 3

2 2 3 (TableForm'd for clarity)

2 2 3

1   1   2
1   1   2
1   2   3
1   2   3
1   2   3
2   1   2
2   1   2
2   2   3
2   2   3
2   2   3

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is

1 1 2

1 1 2

1 2 3

1 2 3

1 2 3

2 1 2

2 1 2

2 2 3

2 2 3

2 2 3

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is (TableForm'd for clarity)

1   1   2
1   1   2
1   2   3
1   2   3
1   2   3
2   1   2
2   1   2
2   2   3
2   2   3
2   2   3
1
source | link

Transpose and Count might be your friend

SeedRandom[125];
data = Sort@RandomChoice[{1, 2}, {10, 2}]
counted = Count[data, #] & /@ data
Transpose@Append[Transpose@data, counted]

with sample data

{{1, 1}, {1, 1}, {1, 2}, {1, 2}, {1, 2}, {2, 1}, {2, 1}, {2, 2}, {2,
2}, {2, 2}}

output is

1 1 2

1 1 2

1 2 3

1 2 3

1 2 3

2 1 2

2 1 2

2 2 3

2 2 3

2 2 3