BitCoin has fluctuated much more than 10% in the last year though: https://www.xe.com/currencycharts/?from=XBT&to=USD&view=1Y

Certainly much more than USD/EUR: https://www.xe.com/currencycharts/?from=EUR&to=USD&view=1Y

A typical volatility index measure like VIX( EVZ ?) could be good reference , there are few VIxes which look bitcoin as priced in USD

10% is an underestimate. BTC fluctuates by 50% or more.