Rick: There could be so many reasons for the jump. A few: Maturing GICs where people were faced buying a 5-yr 2% GIC fixed for the entire term or they could invest in a dividend stock that paid them a 5% currently(2 1/2 times more) and that dividend might grow by 7%+ per year. Many likely chose the latter. 
Company boards recognized that the aging population was attracted to companies that paid dividends (that's been ongoing since 2000) and so focused more on paying and raising dividends. Even many large tech companies began paying dividends.
More people reinvesting, compounding their growth of income.  
With the aging population, more people retiring and withdrawing money from RRSPs and RRIFs.  
A whole lot of money being inherited---a possibility that those passing on were depression babies thus sitting on cash / GICs only and those inheriting invested that money.
My div. income was 34.5% higher in 2015 than 2014--from new money, div. increases and reinvestment.
It can happen.
SFI