Emmalia is a careful investor. She wants to invest in a new stock.

Her potential financial advisor told her that the wealthguarant stock would be a good option, as she might expect an average annual return of roughly 10%. To assess the credibility of the financial adviser's claim, Emmalia has collected the annual returns of the stock over the last five years, which are shown below:

2.10% - 4.17% 6.8% 10% 16.2%
Based on this information, how confident can Emmalia be in the adviser's claim?