The one year returns clearly depends on many factors, some of which are in our control and some are not!
Debt funds: If you go for liquid funds you are likely to make 6.5% to 7.2% in 2018. Longer term debt funds are volatile and returns are not so predictable in 2018.
Equity funds have seen correction in early 2018 but over a long period of say 10 years one can expect a return of 12% to 15% annualised.
So to sum, the short term is not so predictable, but the long term is reasonably optimistic!