In some areas of Florida, manatees gather near spring waters during cold weather because the temperature of the springs is always about 72°F. To protect the manatees and the environment, the government closes these areas to people during certain times of the year. Evaluate the effectiveness of the restrictions since they went into effect in 1985, based on the data below from Ruby Springs.
Manatee Data from Ruby Springs, 1980-2010
Year Manatee Population Manatee Deaths due to Watercraft
1980 273 25
1990 367 10
2000 399 8
2010 453 8