What tax rate is applied to the profits earned in non-deductible traditional IRA contributions which were transferred to a Roth IRA account?

The contributions were made to my Traditional IRA account in 2013 and 2014. All of the contributions were after-tax money and were non-deductible based on Form 5498 of both 2013 and 2014.

 

In September 2022, all of the money in the Traditional IRA account was rolled over to my Roth IRA account. There were some profits. What tax rate is applied to the profits?