The last 10 years tells a story. Most of the parameters have dropped by half or more. Reporting has dropped from around 65 to 70% to 43%. Angling days have dropped by half.
If one defines success rate as catch per unit effort, ie (#steelhead kept + released) / #angler days , then that has dropped by 70% over this time period based on this chart.
If there is anything encouraging (if you could even call it that), is that licenses sold have only dropped by ~10%, for now