A cliche is a phrase that has become ineffective or unoriginal because it has been overused. That said, "Leaps and bounds" is a good example of a cliche.
You can make it sound less biased by being more specific about what "at risk" means and by attributing your information to a credible source. This will help it to sound less like an opinion statement. Other specifics you could add to make it more objective and less biased include specific facts and figures, like specific years during which the number has jumped or an actual percent increase.
Here are some ideas for other ways to say this. You'll have to rewrite and adjust as needed, as I am not exactly sure of what you mean by "at-risk" in this sentence (that could mean a lot of different things as there are a number of reasons a student could be considered "at risk").
- According to _____________, the number of at-risk students who are staying in college for four years has increased by more than ____ percent since the year _____.
- When it comes to at-risk students, the percentage who are remaining in college for at least four years has increased from ____ percent to _____ percent in the past ______ years.
At-risk youth are experiencing greater success in college as their graduation rates at four-year institutions are significantly improving.
The number of at-risk students remaining in college for four years is increasing based on ____________data.