question on ilf day charts

I have been following ING for a while and I have a question on the day charts. The average daily volume is not huge, but at over 600K I would still expect to see some liquidity. Instead, a typical day chart for ILF looks like an extremely small number of extremely large trades. The chart just flat lines with no trades for a long period of time, and then suddenly you see more than 100K shares and the chart stairsteps up or down.

Can someone explain the reason for this? Why are there not large numbers of smaller retail trades?

I am using Yahoo Finance and also Reuters for the charts, using the symbol ILF.AX.