They believe the simian immunodeficiency virus,S.I.V., probably crossed from chimpanzees to humans in the last one hundred years.

VOA: special.2009.09.08

Experts found that two hundred ten rhinos were illegally killed in South Africa in the last three years.

VOA: special.2009.12.14

"Over just the last three years, NHTSAs defect and compliance investigations have resulted in five hundred twenty-four recalls involving twenty-three million vehicles.

VOA: special.2010.02.26

In the last two years, more than one hundred forty countries have signed a United Nations treaty, the Convention on the Rights of Persons with Disabilities.

VOA: special.2009.08.15

The committee noted that the number of days spent by passengers on ships in the area has increased by one hundred fifty percent in the last fifteen years.

VOA: special.2009.12.16