That rate has been fairly steady since 2000, but is an increase from 27 percent in 1990.
Recycled content is calculated by dividing the amount of old corrugated containers (OCC) consumed at mills by containerboard production, and it has been calculated annually since 2000, according to the vice president of the Fibre Box Association, Rachel Kenyon.
Also in 2015, the OCC recovery rate hit an all time high of 92.9 percent.
The Corrugated Packaging Alliance links the rise in recycled content to advancements in the papermaking process.
