# Basicity of subsituted amines [duplicate]

In comparing hydroxylamine, hydrazine, and methylamine for basicity, the order of increasing basicity is hydroxylamine < hydrazine < methylamine.

I tried to reason this trend based on electron donating power of the -$$\ce{OH}$$, -$$\ce{NH2}$$, and -$$\ce{CH3}$$ groups, however that yields the order of basicity: methylamine < hydroxylamine < hydrazine, because more electron-donating power concentrates electron density on the nitrogen atom, making it more basic.

Other factors, such as steric hindrance, do not seem to be impacting anything here, because $$\ce{-OH}$$, $$\ce{-NH2}$$, and $$\ce{-CH3}$$ groups are all around the same size.

What is the key factor that influences the basicity here? I realize that hydrazine has two nitrogen atoms, whereas hydroxylamine and methylamine have one nitrogen atom, so that may be affecting the basicity.