When did a mass exodus take place before?
I began studying in 1976, that year saw a 2% increase.
In 1977 there was a 1% decrease and in 1978 a 1.4% decrease. Then 1979 had an increase of 0.5% and in 1980 an increase of 3.5% with a new all-time peak in pubs.
This was the aftermath of 1975. But there was no "mass exodus."
It will be interesting if 2015-16 bring small decreases. But the new headquarters in 2017 and related hype/exitement could cause another all time peak.
Perhaps there will be small decreases at various times but I think jws will still be around long after I'm gone.