Walk percentage
Walk percentage (also known as Base-on-balls percentage, BB%, or BBP) is a baseball statistic criterion. The purpose of this offensive measurement is to gauge the percentage of a batter's plate appearances that result in the player being walked. A more recently developed statistic than batting average, it is used to determine hitters that have a better plate discipline. References

See also
On-base percentage
Walk-to-strikeout ratio

Batting statistics
Percentages