Use Yield Gap to predict SET index

Average Yield Gap 2000-2009 = 5.5% (as below figure)

Updated 10 year US Bond as of Jan 13 '2014 = 2.85%
http://www.bloomberg.com/quote/USGG10YR:IND

Therefore, use Average Yield Gap to predict Average Index

Average PE = 12 times

From Last Article, let say,as of Jan 22 '14: SET=1290, PE = 14.5
http://marketdata.set.or.th/mkt/marketsummary.do?language=th&country=TH

If use PE = 12, SET = 1067 (consider no GDP growth)

So, Average SET = 1067
Today SET (Jan 22 '14) close at = 1290  ==> Very Expensive???