calculate numerical value of current in inductor resistant circuit.

l=1mH r=3k (ist=1ma at t=0)
i1(t=1us)in ma. i0=1ma
my work. i=i0(1-e^-(t/T))
1*10^-3(1-e^(-1/0.33)
i=0.952ma this is wrong
do I need to add initial current to this(1ma). why is this wrong??