It looks like the US video game industry is starting to show signs of the economic downturn as overall US sales for June were down 31% to US$1.17 billion from US$1.7 billion in 2008, according to The NPD Group.

Industry analyst Anita Frazier notes that it’s the fourth month of year-over-year declines in a row, with June seeing the greatest sales drop since 2000.

But there’s still a silver lining, as NPD’s latest gamer segmentation study suggests that more than four million new people have entered the games market since last year.

While the Xbox 360 is the only platform to see unit sales increase over last June, Nintendo still ruled the charts as consumers snapped up more than 424,000 of the new handheld DSi and more than 342,000 DS devices, bringing the total sales of the DS franchise to 766,000 units this June. The Nintendo Wii saw its 21st consecutive month as the top-selling US home console, selling 362,000 units.

Also of note, video game points and subscription cards saw a 67% spike in dollar sales this June compared to last year.