But the volume of loans the company handles has more than doubled over the same period.

The volume of mortgages has doubled since 1990, he pointed out.

However, within her first two years, the volume of business doubled, and during the third it trebled.

The volume of business data worldwide, across all companies, doubles every 1.2 years, according to estimates.

In just the last 18 months, the volume in these options has doubled, to 600,000 contracts a day.

Then, suddenly, the volume of voices doubled; the other door had opened and footsteps now moved across to his own.

Mason sorted through his mail, the volume of which had doubled.

"When you look at the numbers over the last three years, the volume of airplanes under lease worldwide has almost doubled," he said.

The difference in 1990 is that the volume of both mail and traffic has doubled.

This is not sustainable, particularly in the light of the fact that the volume of air traffic doubles every 10 to 15 years.