YM, Dow spread

Not that it really affects trading, but can anyone tell me why when YM contracts rollover the new contract always has a large difference in price in comparison to the DJIA in contrast to the contract just expired? Thanks..

 

YM futures price "carries" the future quarterly dividends that Dow 30 stocks pay.

 

http://www.programtrading.com/fvalue.htm

 

http://www.cbot.com/cbot/pub/cont_detail/1,3206,1719+8708,00.html