The tax agency said Thursday that in the 2007 budget year it audited one out of every 11 with incomes of $1 million or more. Among those with incomes of $100,000 or less, 99 out of every 100 escaped further IRS scrutiny.

Still, the IRS said its auditing rates were generally up for people of all income levels. The rates were 9.25 percent for those with incomes of more than $1 million, up from 6.3 percent in 2006; 2.87 percent for those with incomes above $200,000, up from 2.57 percent; and 0.93 percent for those earning under $100,000, compared to 0.89 percent the previous year.

Overall, the IRS looked at 1,384,563 returns in fiscal 2007, 1.03 percent of the total individual returns of 134.4 million in the previous calendar year. The audit rate was up 7 percent from the previous year.

There were 31,382 audits of those with $1 million incomes, up 84 percent from the 17,015 audited in 2006.

On the business side, the IRS said the audit focus was on partnerships and mid-market corporations, those with assets between $10 million and $50 million.

The returns of 59,516 businesses were audited in 2007, 0.66 percent of the total and compared to 52,223 in 2006. About one out of six large corporations with assets of $10 million and higher was audited, 9,644 out of 57,357, were audited, down slightly from the previous year.

The tax agency said its enforcement budget in 2007 was largely unchanged from 2006, so it had to focus on areas of growth and potential risk.

It said enforcement revenues in fiscal 2007, from collections and appeals activities, were $59.2 billion, up from $48.7 billion the previous year.

The IRS also noted that 57 percent of individual tax filers filed electronically last year, up from 54 percent in 2006.