It is known that ethyl has a stronger inductive effect than methyl. Its positive inductive effect is greater than methyl.
Then why does ethylamine has a $\mathrm{p}K_\mathrm{b}$ of $3.35$ and methylamine has the $\mathrm{p}K_\mathrm{b}$ of $3.34$ ($\mathrm{p}K_\mathrm{b}$ values in water) Shouldn't the $\mathrm{p}K_\mathrm{b}$ of ethylamine be lower than methylamine?