A riddle

I heard this one today and had a good time puzzling it over. Feel free to ask questions for clarification, I will post the answer in a few days.

You are in a group of 10 people, very soon you will be put in a line.

You will each be given a hat that will either be red or black.

A man will go down the line from back to front and ask you to guess the color of your hat.

If you guess wrong he will kill you, if you guess right you are safe.

You have a chance to strategize with the group before being put in a line.

What is the strategy that guarentees the highest rate of survival?

Rules;

-each person can see everyone in front of them

-you cannot look at your own hat

-the only communication you can make is the guess of your hat color

If there are X people in line, you can guarantee saving (X-1) as long as everyone hears everyone behind them in line.

Edit: HINT Consider how they could guarantee saving two people if the line was only 3 people long. Now consider how that could be scaled up.

Edit the second: Congratulations mardybum430