"Falls by" is a phrase commonly used to describe a decrease or decline in something, such as sales or popularity. If you're tired of using the same phrase repeatedly, there are many synonyms that you can use instead. Some alternatives include "decreases," "drops," "slips," "declines," and "plummets." These words convey a similar meaning to "falls by," but with different nuances and connotations. You can also consider using more specific synonyms such as "tumbles," "slides," or "dips," depending on the context. Using varied vocabulary can make your writing more interesting and engaging, so try experimenting with different synonyms.