>I knew about Ground-hog day just from a movie with Bill Murray and...I don't remember, maybe Andie Mc Dowell?

Yes it was Andie McDowell. According to the site below the turn out for the event has grown dramatically since the film was made, even though they changed the location in the film.

"Columbia Pictures decided to film the movie in a location more accessible to a major metropolitan center. The highways in and around Punxsutawney were few, so Woodstock, Illinois was chosen as the site. Unfortunately, Woodstock's landscape doesn't have Pennsylvania's scenic rolling hills. Nevertheless, adjustments were made for the production. The actual Gobbler's Knob is a wooded hill with a beautiful view; the Gobbler's Knob in the movie is moved to the town square. The Punxsutawney Gobbler's Knob was recreated to scale in Woodstock's town square based on detailed notes and videos the crew made on it's visit to Punxsutawney."
"In 1997, there were 35,000 visitors in Punxsutawney, five times the Jefferson County town's 6,700 population."
http://www.stormfax.com/ghogday.htm#Movie