Florida is being invaded by giant African land snails. The snails are the size of rats and are an invasive species—an animal or a plant that moves into an area and harms native species. The snails cause harm by eating away the walls of houses (the calcium is good for their shells), spreading diseases, and eating Florida's native plants.
The pests were first spotted two years ago. State officials have spent about $6 million on efforts to get rid of the snails, including sending a team of 45 people to hunt for the snails. They recently tried something new—sending Labrador retrievers to sniff out the snails. Now Florida officials think they have the snails contained in the Miami area. About 128,000 snails have been found and destroyed.
(Subscribers, for more on invasive species, see page 4 of the October 28 digital edition).
Last year, the average number of snails found per day was 1,000. Now it's about 100 per day. What is the percent decrease of giant African land snails found per day?