Of the 75,000 species assessed by the IUCN Red List (by end 2014), 20,000 species have been listed as threatened (classed as Vulnerable, Endangered or Critically Endangered)
The 2014 Living Planet Index tracks trends of over 3000 species of vertebrates (mammals, reptiles, amphibians, birds and fish). Between 1972 and 2010, the populations have decreased by 52%.
Globally, nature’s assets have been valued at $125 trillion per year.
Note: All statistics here are what I have learnt from the Introduction to Conservation course from National Geographic.