Estimates vary about the fishing market for the Great Lakes region. In 2007, one estimate of the total market for fishing in the Great Lakes, including commercial and recreational fishing, was $4 billion annually. Another estimate was more than $7 billion. But since high levels of pollution were discovered in the 1960s and 1970s, there has been continued debate over the desired intensity of commercial fishing. Commercial fishing in Lake Erie has been hurt by pollution as well as government regulations which limit the size of their catch; one report suggested that the numbers of fishing boats and employees had declined by two-thirds in recent decades. Another concern had been that pollution in the lake, as well as toxins found inside fish, were working against commercial fishing interests.