A 2003 report said this activity had reached unsustainable levels and was putting large mammals at stake.

This regulation will ensure that lending does not reach the low prices and unsustainable levels of 2007.

By the 1650s, the officer-to-man ratio in the Army had reached the unsustainable levels of one to four.

That could potentially drive up the overall cost of cancer treatment to unsustainable levels, they say.

Still, he said, some species continue to be poached at unsustainable levels for other markets.

Unless revenues increase at a similar pace, such spending will cause federal debt to grow to unsustainable levels.

How could stock prices be pushed up to such irrational and unsustainable levels?

I think the current price of energy is at an unsustainable level.

"However, marketing rose to what I consider to be unsustainable levels."

If they do so at an unsustainable level there will be no resources for their children or grandchildren in the future.