We present experimental results obtained with a two-dimensional silo discharging under gravity through an
orifice at the flat bottom. High-speed measurements provide enough time resolution to detect every single bead
that goes out and this allows the measurement of the flow rate in short-time windows. Two different regimes
are clearly distinguished: one for large orifices, which can be described by Gaussian fluctuations, and another
for small orifices, in which extreme events appear. The frontier between those two regimes coincides with the
outlet size below which jamming events are frequent. Moreover, it is shown that the power spectrum of the
flow-rate oscillations is not dominated by any particular frequency.