When describing a sharp decline or drop in something, the word "plummeting" is often used. However, there are a number of synonyms that can be used to convey the same idea with slightly different nuances. For example, instead of "more plummeting," one might use "further plunging," "rapid descent," "precipitous drop," or "steep nosedive." Each of these phrases adds a slightly different emphasis to the idea of something falling or decreasing rapidly. Alternately, one might use adjectives like "steep," "sharp," or "dramatic" to describe the nature of the decline.