Shoreline litter data research shows policies caused a relative decrease in the percentage of plastic bags.
In 2014, shops started charging a minimum of 5p per bag in attempt to reduce waste.
Customers who recycle the cans and drinks bottles will have the new fee returned to them.
But environmentalists say the government must go much further to tackle the plastic problem.
Businesses are no longer allowed to provide customers with single-use bags.
The increase is welcomed by environmentalists, but retail bodies say it is excessive.
The figure is obtained by BBC News NI on the day the bag charge goes from 5p to 25p.
Single-use plastic carrier bags in English shops now cost 10p, twice the previous price.
The price rise for single-use bags will be extended to all businesses in England from 21 May.
