This is the 480th most frequent Hebrew word.
בהרבה
"בהרבה" means "in many" or "by much."
Here, 'בהרבה' is used to indicate a significant improvement or advancement.
הוא השתפר בהרבה מאז הפעם האחרונה.
He has improved a lot since the last time.
In this context, 'בהרבה' emphasizes the degree of interest being greater.
הספר הזה יותר מעניין בהרבה מהקודם.
This book is much more interesting than the previous one.
The usage of 'בהרבה' here quantifies and describes the frequency of occurrences.