Any differences between the two music groups' average improvements may have been due to chance, the study shows.

The average annual improvement was 0.3%; some mills have already reached extraction efficiencies of 98%.

To date, there has been an average improvement of 25% in students' level of English.

For those with moderate depression who were treated, the average improvement was 71 percent, from 62 days of disability a year to just 18.

The average improvement for those using the clay addition was 18% higher than for non-clay users.

However, measures of patient safety showed an average annual improvement of only 1 percent.

To date there has been an average improvement in measured language ability of 25%.

Those 11 showed an average improvement of 6.25% on their times, compared to 2.5% of the other skaters using regular speed skates.

"This year we think the average improvement at our centers is a little over 150 points."

That, in fact, has been the average annual improvement since 1995, when the boom got rolling.