Who Picks The Number? And Why?

From a recent ALS Association announcement --

http://capwiz.com/alsa/issues/alert/?alertid=63056586

We are excited to let you know that on January 16, Congress passed legislation that included ...  an additional $6.5 million for the National ALS Registry. The funding for the Registry is an 11% increase over last year! The legislation now heads to President Obama who is expected to sign it into law.

... The fact that Congress increased funding for the Registry in a year when cuts were the norm is a testament to the effectiveness of your advocacy. 

Every year we advocates are given a dollar number (from ALSA) needed for the CDC ATSDR national ALS Registry to continue.  We advocate to our legislators.  The number gets a very predictable haircut, and the CDC ATSDR has a budget for a well-funded project.  Every year.

Who comes up with the number?  What are the components.  Why did we ask for $10 million and not $15 or $20 or $1 or $5 million. Nobody talks to us advocates about the number.  Nobody discusses it at the invitation-only annual meeting per the recently published meeting minutes.

It just is.

Who picks the number?  Why that particular number?

Very simple questions.  The answers will make effective advocates even better.