Miki Nishino

Nishino Miki (Mikichan)
Member of the Japanese idol girl group AKB48 under Team 4. She is also a member of AKB48's subgroup Tentoumu Chu!
b.4/4/1999
c2015: I think her height was 157.5 cm last year, and 155 cm the year before. She might get taller by about two centimeters a year.

Another point of her growth spurt may be her body form. I see she got in trouble with her original Team 4 outfit recently.
The outfit fit perfectly in the debut video, but it was almost outgrown by the second year. The shorts went from loose to tight fitting.
Another year passed and that just made it worse. The shorts are now straining over the front of her hips and a shirt button has come undone.
Her rounder buttocks pushed out the back. Also her bosom is bigger:

That has not only happened to her, but to many girls in their growth spurts.
- (Teamk-oshi, Kenkyuusei)