Only about 3.2 % of girls' first names in the United States begin with the letter B…
This means that the initial B is only slightly less common than average – with 26 letters in the alphabet, each initial occurs on average in 3,8 % of all girls' first names. However, 3.8 % is just the average. Of course, the initials of girls' first names aren’t that evenly distributed, with some letters being rarer than others. In the US, the initials A and S are particularly frequent for girls' first names, while very few names begin with the letters U and X.