This is based off of estimations/reports by forbes/celeb net worth/Ibetimes etc..So some figures are probably higher or lower. These figures are the most recent updates. Wait a bit if you think the figures are not accurate and they will most likely be updated by forbes/celeb net worth eventually.

Beyonce: 450m$
Britney: 165m$
Rihanna: 120m$
Shakira: 220m$
Katy: 200m$
Taylor: 200m$
Gaga: 250m$
Madonna: 520m$
Ariana : 12m$
Miley: 160m$
Demi: 15m$
Selena: 16m$
Nicki: 60m$
Iggy: 6m$
Mariah: 510m$

http://www.celebritynetworth.com/
http://www.forbes.com/fdc/welcome_mjx.shtml

Ciara 25m$

Rih would have more... but she had bad management/contract for the longest time.

Slay at Miley with 160 million... Hannah Montana

Ari's coming to snatch all of them

Selena is worth more. She was just paid 3 million for Pantene, 5 or 10 million for hotel transylvania 2, plus iPhone 6 commercial,

Not Nicki having 10x more than Iggy

and I also didn't know Miley had that much! :O

Gaga hanging strong

Britney: 165m$
No way is that right...

people need to learn the difference between net worth and income

Hilary Duff 25M$

How is that possible

There's NO way

exactly.
this is net worth not income.
example: katy made 135m$ last year. this does not mean all of it goes to her. hence why her net worth is 200m$

britney generated a ton of money but this does mean she got all of it. her label probably had a tight contract with her.

Shakira's number is so low. I'm sad. How will she survive?

Because Queen was huge at one point