Nothing goes is a straight line for ever! After a long period of time you know something scary is coming!
Stats from the 100 years trend of Dow Jones Industrials Index.
10 year cycle of years starting with a 7 on the end (1987, 1997, 2007) and years ending with a 8 on the end (1988, 1988, 2008).
During the 2years of 2017 and 2018 the odds are:
1) 20% chance the up trend will continue at the same pace with no correction greater than 12%.
2) If (1) occurs and a major correction is delayed the odds increase a 20% plus correct is very likely.
3) 80% chance the trend does not continue at same pace and will either fall or trend flat.
4) 40% chance price will trend higher or go flat, with no major corrections.
5) 60% chance some sort of correction greater than 12.5%.
6) 40% chance some sort of correction greater than 20%.
7) 40% chance some sort of correction greater than 30%.
8) 30% chance some sort of correction greater than 50%.
9) Two major bearish corrections in a row is unlikely [subject to (2) above].
Corrections come in many forms, fast or slow, no one knows what is in store this time. From above you can bet on (1) and (3).