Percentage on last value

[JS-Trainspot]

Love your library!!!

Would it be possible to add a option to display the percentage based on the last value? Currently it's possible to display the percentage based on the max value, but I'm looking for a way to display the percentage based on the last value.

Example:

• Data: 300, 200, 150, 40
• Current percentages: 100%, 67%, 50%, 13%
• Percentage based on last value: 100%, 67%, 75%, 27%

Thank you