Footnote
a It is estimated, for example, that in 1999 the deficit reached 20 percent. This means that the amount of natural resources humans used during that 12-month period took more than 14 months to replace.
a It is estimated, for example, that in 1999 the deficit reached 20 percent. This means that the amount of natural resources humans used during that 12-month period took more than 14 months to replace.