| Period  | Total | Less than 2.0 percent | 2.0-4.9 percent | 5.0-9.9 percent | 10.0-14.9 percent | 15.0-19.9 percent | 20.0 percent and over |
|---------|-------|-----------------------|-----------------|-----------------|-------------------|-------------------|-----------------------|
| 1987:Q1 | 100   | 35.9                  | 32.7            | 21.4            | 6.8               | 2.3               | 1                     |
| 1987:Q2 | 100   | 39.6                  | 33.5            | 19.3            | 5.1               | 1.7               | 0.8                   |
| 1987:Q3 | 100   | 43                    | 33              | 17              | 4.9               | 1.3               | 0.5                   |
| 1987:Q4 | 100   | 50.3                  | 30.6            | 14.4            | 3.3               | 0.9               | 0.3                   |
| 1988:Q1 | 100   | 49.1                  | 30.8            | 15.7            | 3.2               | 0.9               | 0.4                   |
| 1988:Q2 | 100   | 51.7                  | 31.9            | 13.1            | 2.4               | 0.6               | 0.3                   |
| 1988:Q3 | 100   | 54                    | 31.3            | 12              | 2.1               | 0.4               | 0.3                   |
| 1988:Q4 | 100   | 59                    | 28.9            | 9.7             | 1.9               | 0.4               | 0.2                   |
| 1989:Q1 | 100   | 57.6                  | 29.3            | 10.6            | 1.9               | 0.4               | 0.2                   |
| 1989:Q2 | 100   | 60.2                  | 29.3            | 8.3             | 1.5               | 0.6               | 0.2                   |
| 1989:Q3 | 100   | 61.7                  | 27.6            | 8.5             | 1.6               | 0.4               | 0.2                   |
| 1989:Q4 | 100   | 65.8                  | 25.1            | 7.6             | 1.2               | 0.2               | 0.1                   |
| 1990:Q1 | 100   | 61.94                 | 26.77           | 9.16            | 1.45              | 0.48              | 0.19                  |
| 1990:Q2 | 100   | 65.42                 | 24.95           | 7.96            | 1.29              | 0.31              | 0.07                  |
| 1990:Q3 | 100   | 66.62                 | 24.85           | 7.3             | 1.01              | 0.19              | 0.02                  |
| 1990:Q4 | 100   | 69.64                 | 22.69           | 6.44            | 1.03              | 0.2               | 0                     |
| 1991:Q1 | 100   | 65.09                 | 25.49           | 7.65            | 1.45              | 0.22              | 0.1                   |
| 1991:Q2 | 100   | 65.74                 | 25.54           | 7.06            | 1.27              | 0.25              | 0.15                  |
| 1991:Q3 | 100   | 67.31                 | 25.24           | 6.29            | 0.92              | 0.22              | 0.02                  |
| 1991:Q4 | 100   | 70.82                 | 22.3            | 5.82            | 0.69              | 0.3               | 0.08                  |
| 1992:Q1 | 100   | 66.33                 | 24.65           | 7.55            | 1.06              | 0.3               | 0.1                   |
| 1992:Q2 | 100   | 68.03                 | 24.3            | 6.45            | 0.96              | 0.15              | 0.1                   |
| 1992:Q3 | 100   | 71.63                 | 22.12           | 5.38            | 0.69              | 0.13              | 0.05                  |
| 1992:Q4 | 100   | 76.24                 | 18.84           | 3.93            | 0.81              | 0.16              | 0.03                  |
| 1993:Q1 | 100   | 71.73                 | 21.84           | 5.33            | 0.89              | 0.18              | 0.03                  |
| 1993:Q2 | 100   | 74.42                 | 20.44           | 4.41            | 0.58              | 0.11              | 0.05                  |
| 1993:Q3 | 100   | 76.61                 | 19.06           | 3.57            | 0.63              | 0.11              | 0.03                  |
| 1993:Q4 | 100   | 80.74                 | 15.75           | 2.83            | 0.57              | 0.11              | .                     |
| 1994:Q1 | 100   | 79.29                 | 16.73           | 3.33            | 0.51              | 0.14              | .                     |
| 1994:Q2 | 100   | 80.87                 | 16.24           | 2.42            | 0.41              | 0.05              | .                     |
| 1994:Q3 | 100   | 83.48                 | 13.68           | 2.45            | 0.33              | 0.03              | 0.03                  |
| 1994:Q4 | 100   | 85.47                 | 12.32           | 1.9             | 0.23              | 0.06              | 0.03                  |
| 1995:Q1 | 100   | 81.6                  | 15.32           | 2.68            | 0.23              | 0.09              | 0.09                  |
| 1995:Q2 | 100   | 82.04                 | 15.03           | 2.56            | 0.2               | 0.12              | 0.06                  |
| 1995:Q3 | 100   | 82.8                  | 14.34           | 2.42            | 0.29              | 0.03              | 0.12                  |
| 1995:Q4 | 100   | 83.44                 | 13.99           | 2.15            | 0.27              | 0.09              | 0.06                  |
| 1996:Q1 | 100   | 78.12                 | 17.43           | 3.61            | 0.57              | 0.15              | 0.12                  |
| 1996:Q2 | 100   | 78.02                 | 17.22           | 4.01            | 0.57              | 0.12              | 0.06                  |
| 1996:Q3 | 100   | 79.18                 | 17.06           | 3.11            | 0.49              | 0.09              | 0.06                  |
| 1996:Q4 | 100   | 81.88                 | 15.41           | 2.32            | 0.25              | 0.09              | 0.06                  |
| 1997:Q1 | 100   | 79.06                 | 16.74           | 3.7             | 0.37              | 0.06              | 0.06                  |
| 1997:Q2 | 100   | 80.51                 | 15.8            | 3.25            | 0.34              | .                 | 0.09                  |
| 1997:Q3 | 100   | 81.78                 | 15.25           | 2.66            | 0.16              | 0.09              | 0.06                  |
| 1997:Q4 | 100   | 84.46                 | 12.87           | 2.45            | 0.13              | 0.06              | 0.03                  |
| 1998:Q1 | 100   | 80.61                 | 16.29           | 2.84            | 0.13              | 0.07              | 0.07                  |
| 1998:Q2 | 100   | 80.78                 | 15.86           | 2.94            | 0.33              | 0.07              | 0.03                  |
| 1998:Q3 | 100   | 80.27                 | 16.24           | 3.06            | 0.3               | 0.1               | 0.03                  |
| 1998:Q4 | 100   | 81.67                 | 15.13           | 2.83            | 0.3               | .                 | 0.07                  |
| 1999:Q1 | 100   | 77.17                 | 17.75           | 4.46            | 0.54              | 0.03              | 0.03                  |
| 1999:Q2 | 100   | 78.68                 | 16.86           | 3.85            | 0.61              | .                 | .                     |
| 1999:Q3 | 100   | 80.36                 | 15.87           | 3.39            | 0.34              | 0.03              | .                     |
| 1999:Q4 | 100   | 84.75                 | 12.56           | 2.37            | 0.28              | 0.03              | .                     |
| 2000:Q1 | 100   | 81.77                 | 14.81           | 2.92            | 0.46              | 0.04              | .                     |
| 2000:Q2 | 100   | 82.2                  | 15.1            | 2.4             | 0.3               | 0                 | 0                     |
| 2000:Q3 | 100   | 83.01                 | 14.87           | 1.72            | 0.36              | 0.04              | .                     |
| 2000:Q4 | 100   | 85.04                 | 12.83           | 1.81            | 0.33              | .                 | .                     |
| 2001:Q1 | 100   | 80.25                 | 16.88           | 2.61            | 0.18              | 0.07              | .                     |
| 2001:Q2 | 100   | 80.23                 | 16.56           | 2.96            | 0.18              | 0.07              | .                     |
| 2001:Q3 | 100   | 78.72                 | 17.76           | 3.19            | 0.33              | .                 | .                     |
| 2001:Q4 | 100   | 80.02                 | 17.26           | 2.53            | 0.15              | 0.04              | .                     |
| 2002:Q1 | 100   | 76.82                 | 19.26           | 3.69            | 0.19              | 0.04              | .                     |
| 2002:Q2 | 100   | 76.83                 | 19.64           | 3.11            | 0.38              | 0.04              | .                     |
| 2002:Q3 | 100   | 77.79                 | 18.78           | 3.24            | 0.15              | 0.04              | .                     |