The automobile industry announced U.S. sales figures for June late yesterday. Contrary to last month, when the automakers combined to post the strongest month of sales since August, June sales were down approximately 4.5%, falling to the lowest levels since February 2003.

Despite an impressive 10% sales jump in June for its Cadillac models, General Motors (NYSE:GM) reported a 15.5% decrease in sales compared to a year ago. Car and truck sales were equally disappointing for the world's leading automaker with both segments declining 15%. You might be able to forgive GM's truck division, considering it was up against its record-setting performance last year. I also suppose some sales were pushed up last month as a result of the plethora of incentive programs, which encouraged more buyers. But, I'm really just making excuses that don't justify a 15% drop.

Ford (NYSE:F) didn't fair much better, generating a decrease of 7.7%. Car sales for the No. 3 automaker plummeted 17%. Despite the popularity of the redesigned F-150, which helped sales of Ford's F-Series climb for the 10th month in a row, truck sales slipped 2.7%. Potential Ford buyers appear to be waiting for the launch of more new designs, including the Mustang, which is due out later this year.

The smallest of the Big Three, DaimlerChrysler (NYSE:DCX), was the only one able to generate positive sales growth. Its Chrysler group was able to eke out a 1% gain thanks to the success of its new Chrysler 300 model.

Once again, unlike the U.S. manufacturers, each of the top three Japanese automakers reported increased sales for June. Both Honda (NYSE:HMC) and Toyota (NYSE:TM) posted their best June sales ever, as did Nissan's (NASDAQ:NSANY) Infinity brand.

Nissan reported the largest increase when its sales climbed 9%. Toyota also refuses to slow down and recorded a 5.2% increase in sales for June.

Honda reported a small increase of 1.1% thanks to its popular Odyssey and Accord models, which performed well, but recently were the subject of some negative news. Acura, Honda's luxury line, also helped prop up sales with an 8.2% increase.

As a result of these sales trends, the Japanese manufactures continue to chip away at the market share of the U.S. leaders. The Big Three have given up 3% of their market share over the last year and now control 58.5% of the market. Based on comments of company representatives, the situation is unlikely to improve in the near future. Officials at GM and Ford caution that it will be difficult to recover in the second half of the year while Toyota management is anticipating an upswing in sales this summer.

Fool contributor Mike Cianciolo welcomes feedback and doesn't own any companies in this article.