Recycling of single-use plastic water bottle containers reached 38.6 percent for 2011, more than doubling the rate from seven years ago, according to a new study.

The recycling rate for polyethylene terephthalate (PET) bottles increased nearly 20 percent from the previous year’s rate of 32.3 percent, according to data from the Sonoma, Calif.-based National Association for PET Container Resources (NAPCOR)

And the New York-based Beverage Marketing Corp. (BMC) reported that the average weight of a 16.9-ounce, single-serve PET plastic water bottle dropped by almost 47.8 percent during the past 11 years to 9.9 grams, the Alexandria, Va.-based International Bottled Water Association (IBWA) stated in a news release.

According to the internal NAPCOR study, 500 million pounds of PET plastic water bottles were reclaimed for recycling in 2011, which is the most recent data.

BMC data showed that the bottle weight reductions have saved 3.3 billion pounds of PET resin since 2000.