A disgruntled pet store owner abandoned an unknown number of groundhogs on a small island in 1996 . Since then it has been determined that the average rate of change of the groundhog population was 4 groundhogs per year and that the groundhog population was a linear function of time. When the abandoned groundhogs were discovered in 2001 , there were 376 groundhogs on the island. How many groundhogs did the disgruntled pet store owner originally leave on the island?