It is commonly acceptable to say 'inflation began', but it's not good English among economists, nor it should be otherwise.
If, on the other hand that certain time period is a part of greater period of observance, it is acceptable to say so. But, again, in context LeUyenHoc provided, it does not appear to be logical.
Some other contexts may seem better for it:
e.g. began to climb/rise, began to accelerate.I.