What % of daily volume do institutional investors aim for when executing large block trades using a VWAP algorithm?

Is there an industry standard for what % of daily volume should be bought/sold during a large block trade to avoid affecting the price too much?

Let's say you had a large institutional investor using a VWAP/TWAP/Iceberg method to sell a large block of Shares, how much of the daily volume would they be looking to sell?