| Year | 2004 | 2005 | 2006 | 2007 | 2008 |
| Sample size | 1481 | 1854 | 1873 | 1964 | 2005 |
| Number of auditors | 108 | 117 | 120 | 109 | 113 |
| Year | 2009 | 2010 | 2011 | Average 2004-2011 | Total 2004-2011 |
| Sample size | 2010 | 2040 | 2083 | 1914 | 15,310 |
| Number of auditors | 112 | 110 | 110 | 112.375 | 199 |
| Audit Fee Statistics (million yen) | |||||
| Year | 2004 | 2005 | 2006 | 2007 | 2008 |
| Mean | 67.03 | 68.94 | 86.30 | 95.96 | 73.36 |
| Median | 43.40 | 42.00 | 44.00 | 48.00 | 39.70 |
| St. Dev. | 168.94 | 195.56 | 355.30 | 384.06 | 149.85 |
| Year | 2009 | 2010 | 2011 | Average 2004-2011 | |
| Mean | 75.33 | 74.99 | 72.33 | 77.03 | |
| Median | 40.00 | 39.00 | 38.00 | 42.00 | |
| St. Dev. | 154.45 | 161.57 | 150.53 | 233.33 | |
| Year | Average 2004-2005 | Average 2006-2011 | Relative Change (%) | ||
| Mean | 68.09 | 79.52 | 17% | ||
| Median | 42.00 | 42.00 | 0% | ||
| St. Dev. | 184.19 | 245.23 | 33% | ||