Period

Overpayment

Underpayment

Before 1-1-75

6%

6%

1-1-75 to 1-31-76

9%

9%

2-1-76 to 1-31-78

7%

7%

2-1-78 to 1-31-80

6%

6%

2-1-80 to 1-31-82

12%

12%

2-1-82 to 12-31-82

20%

20%

1-1-83 to 6-30-83

16%

16%

7-1-83 to 12-31-83

11%

11%

1-1-84 to 6-30-84

11%

11%

7-1-84 to 12-31-84

11%

11%

1-1-85 to 6-30-85

13%

13%

7-1-85 to 12-31-85

11%

11%

1-1-86 to 6-30-86

10%

10%

7-1-86 to 12-31-86

9%

9%

1-1-87 to 3-31-87

8%

9%

4-1-87 to 6-30-87

8%

9%

7-1-87 to 9-30-87

8%

9%

10-1-87 to 12-31-87

9%

10%

1-1-88 to 3-31-88

10%

11%

4-1-88 to 6-30-88

9%

10%

7-1-88 to 9-30-88

9%

10%

10-1-88 to 12-31-88

10%

11%

1-1-89 to 3-31-89

10%

11%

4-1-89 to 6-30-89

11%

12%

7-1-89 to 9-30-89

11%

12%

10-1-89 to 12-31-89

10%

11%

1-1-90 to 3-31-90

10%

11%

4-1-90 to 6-30-90

10%

11%

7-1-90 to 9-30-90

10%

11%

10-1-90 to 12-31-90

10%

11%

1-1-91 to 3-31-91

10%

11%

4-1-91 to 6-30-91

9%

10%

7-1-91 to 9-30-91

9%

10%

10-1-91 to 12-31-91

9%

10%

1-1-92 to 3-31-92

8%

9%

4-1-92 to 6-30-92

7%

8%

7-1-92 to 9-30-92

7%

8%

10-1-92 to 12-31-92

6%

7%

1-1-93 to 3-31-93

6%

7%

4-1-93 to 6-30-93

6%

7%

7-1-93 to 9-30-93

6%

7%

10-1-93 to 12-31-93

6%

7%

1-1-94 to 3-31-94

6%

7%

4-1-94 to 6-30-94

6%

7%

7-1-94 to 9-30-94

7%

8%

10-1-94 to 12-31-94

8%

9%

1-1-95 to 3-31-95

8%

9%

4-1-95 to 6-30-95

9%

10%

7-1-95 to 9-30-95

8%

9%

10-1-95 to 12-31-95

8%

9%

1-1-96 to 3-31-96

8%

9%

4-1-96 to 6-30-96

7%

8%

7-1-96 to 9-30-96

8%

9%

10-1-96 to 12-31-96

8%

9%

1-1-97 to 3-31-97

8%

9%

4-1-97 to 6-30-97

8%

9%

7-1-97 to 9-30-97

8%

9%

10-1-97 to 12-31-97

8%

9%

1-1-98 to 3-31-98

8%

9%

4-1-98 to 6-30-98

7%

8%

7-1-98 to 9-30-98

7%

8%

10-1-98 to 12-31-98

7%

8%

1-1-99 to 3-31-99

7%

8%

4-1-99 to 6-30-99

8%

8%

7-1-99 to 9-30-99

8%

8%

10-1-99 to 12-31-99

8%

8%

1-1-00 to 3-31-00

8%

8%

3-1-00 to 6-30-00

9%

9%