I do not understand how You expected inflation in the first year of the currency?
inflation = current(monetary base) / 1_year_ago(monetary_base, right?
The chart shows instantaneous annualized inflation.
Annualized inflation of the monetary base (MB) is calculated as follows, where T is a time period in years:
inflation = [MB(now) - MB(now - T)] / MB(now - T) / T
If T=1, then the equation calculates the proportional increase in the money supply since one year ago, which is probably how you're thinking of inflation. If you calculate the limit of the equation as T approaches zero, then you get the instantaneous annualized inflation, which is what is shown in the chart.