The number of winners is greater than the number of DV visas available.
Each year approximately 100,000 DV Lottery applicants are selected as winners of the Green Card Lottery and become eligible to request a US permanent resident card. The winners are selected at random by a computer-generated lottery.
Only the first 55,000 candidates who decide to proceed with their visa cases and who successfully complete the additional visa paperwork and interview, will receive green cards. Therefore, you must be prepared to act immediately to request your US visa as soon as you receive notice of being selected.