When we write vectors as matrices, we tend to write an $n$-dimensional vector vector as $n \times 1$ column matrix. We emphasize that the gradient vector is defined only for scalar-valued functions. For vector valued functions, we will stick with viewing the derivative as a matrix.
Gloomy Addiction Relapse Statistics. Drug and alcohol rehab statistics show that the percentage of people who will relapse after a period recovery ranges from 50% to 90%. This is a frightening statistic and it is often used as justification for those who wish to carry on with their addiction.
Updated December 26, 2016. If you tried to quit drinking or using drugs, but had a relapse and returned to drinking or using, you are not alone. Statistics indicate that up to 90 percent of people who try to quit have at least one relapse before achieving long-term sobriety. In recovery circles, it's called a slip, or falling back to previous behaviors.