@albbg: I've been around long enough to know that I've been right, and i've been wrong and i'll be right again and I'll be wrong again.
In this particular case, I intended to estimate the voltage across the resistor, but the spice graph is of the secondary coil. Another error.
@SPB: try BradtheRad's suggestion: rerun the simulation, this time with 10H and 0.1H instead of 2000H and 20H. Its not 4, as Brad suggests, but it is a lot closer to 4 that 2000.
Also, use albbg's suggestion to use more simulation points. Use the same time scale, but up the data points by a factor of 10. This will lengthen the simulation time by a factor of 10 (at least). But it looks like the simulation you posred took 0.05 seconds, its not a problem .