Unless otherwise stated, instrument procedures use the standard IFR climb gradient of

Explanation

AIM 5-2-9 states that, unless a higher gradient is published, obstacle clearance on departure assumes the aircraft maintains a minimum climb gradient of 200 feet per nautical mile to the minimum IFR altitude. A gradient is expressed per nautical mile, not per minute, and 400 feet per nautical mile is a non-standard gradient that would have to be published.