Percentage in Lightning Components is not working correctly

The Spring'18 Release Notes reveal, that this will be fixed for lightning:input in the upcomming release:

lightning:input

formatter—The percent-fixed formatter is new for type="number". It displays your input value as is, for example, entering 10 results in 10%. Additionally, the percentage value is now rounded off to the last decimal point when the step value is provided. For example, when step="0.001" and a value of 0.12345 is provided with the percent formatter, you see 12.345% instead of 12% on blur. Similarly, when step="0.001" and a value of 12.3456 is provided with the percent-fixed formatter, you see 12.346%.

And I just verified that formatter="percent-fixed" fixed the issue for lightning:input.