Part of the difference in price from 5 years ago to current is the return of capital.  There is the yield component, but on top of that, laddered funds are returning some of your capital over time.  If you bought the fund 5 years ago, I guarantee you that your Adjusted Cost Base is less than $20.
If you are worried about price declines as interest rates increase, buy actual bonds. If you don't have the capital or interest in doing so, stick with a laddered corporate bond.
There are lower cost alternatives to CBO, but I still hold some of this.