In the past decade, a decreasing percentage of money spent on treating disease X went to pay for standard methods of treatment, which are known to be effective though they are expensive and painful. An increasing percentage is being spent on nonstandard treatments, which cause little discomfort. Unfortunately, the nonstandard treatments have proved to be ineffective. Obviously, less money is being spent now on effective treatments of disease X than was spent ten years ago.
The statement 'The total amount of money spent on treating disease X slowly declined during the past decade' if assumed, allows the conclusion above to be properly drawn.