Finding information on if it was universally adopted is proving difficult. Best I could find is when states started enacting legislation against 3-Cueing. Mississippi was the first to require phonics be taught to children back in 2013, and they are the only state in the OP’s graph to show a strong improvement since 2015 (even though it’s still not reading at grade-level). Unfortunately Covid threw a wrench in our ability to suss out if eliminating 3-cueing is helping, as even if it did, the lack of schooling during that period seems to have really set back all of the kids who went through it, as they can’t really benefit from teaching phonics if they’re receiving it poorly through tele-schooling.
Finding information on if it was universally adopted is proving difficult. Best I could find is when states started enacting legislation against 3-Cueing. Mississippi was the first to require phonics be taught to children back in 2013, and they are the only state in the OP’s graph to show a strong improvement since 2015 (even though it’s still not reading at grade-level). Unfortunately Covid threw a wrench in our ability to suss out if eliminating 3-cueing is helping, as even if it did, the lack of schooling during that period seems to have really set back all of the kids who went through it, as they can’t really benefit from teaching phonics if they’re receiving it poorly through tele-schooling.