Estimated Effort Breakdown in the Waterfall Process

I am posting this here as an informational item. Hope it is useful.

Estimated Effort Breakdown in the Waterfall Process

Requirements: 15-20 percent,
Analysis and Design: 15-20 percent,
Construction (code and unit testing): 25-30 percent,
System Testing: 15-20 percent,
Implementation: 5-10 percent.