How many years had Penelope been putting off the wooers in the odyssey?

In Homer's "The Odyssey," Penelope had been putting off the suitors for about three years. She cleverly delays the suitors by claiming she must finish weaving a burial shroud for her father-in-law, Laertes. Each night, she secretly unravels her work, maintaining the ruse and holding off the suitors until Odysseus returns.