I want to know the answer to the following question:
Shell became a major shareholder in Woodside after a takeover attempt was blocked in what year?
All the background I'm provided with is that "Shell became a major shareholder in Woodside after a 2001 takeover attempt was blocked by then federal Treasurer Peter Costello and the corporation has been open about its intention to sell its stake in Woodside as part of its target to shed assets.". Is that enough to answer the question?