The average MAJOR declines from a top, since 1994, in USDJPY are 31% in 27 months. USDJPY is currently down around 21%. The average would take us down to $86 in September 2017 - a year from now.
The interesting thing is what happens after a +20% decline. The following bounce-average is 13%. That would mean from $100, USDJPY could go as high as $113 in the coming months.