This chart shows how much the bounties of the Straw Hat crew increase as the story progresses.

click here to enlarge

Trivia:

1 berry (currency in the One Piece world) roughly equals 1 Japanese Yen. So 100 berries would be about 1 US Dollar.

Luffy gained his first bounty of 30million berries by defeating Arlong during the East Blue Saga.

Zoro gained his first bounty of 60million berries by defeating Mr. 1 (Daz Bones) of Baroque Works during the Alabasta arc.

The rest of the Staw Hats (except Robin and Brook) gained their first bounties after the events of Enies Lobby.

Robin and Brook are the only Straw Hat members who had bounties prior to joining the crew.

Jimbe is the latest member to join the crew but his current bounty is unknown. The world government withdrew his former bounty of 400million berries when he became a Shichibukai (Warlord).

Chart facts:

Luffy's current bounty of 1.5billion berries is so high compared to the rest of his crew that it has gone off the chart!

Luffy's current bounty is more than the rest of his crew combined.

You can see clearly (where the lines cross) when someone's bounty over-takes another member of the crew.

Usopp's bounty increased by almost 7x after the events of Dressrosa, over-taking 4 other members and becoming the 3rd highest in the crew.

Chopper's bounty is in there... somewhere...

I spelled Zoro wrong...

Let me know what you think in the comments! I'll add more facts and trivia later.