In 1985 the first catalyzed cars entered certain European markets such as Germany. At first, the availability of unleaded petrol was limited and sales were small. In Sweden, catalyzed vehicles became allowed in 1987, benefitting from a tax rebate to boost sales. By 1989 the Swiss/Swedish emissions rules were tightened to the point that non-catalyzed cars were no longer able to be sold. In early 1989 the BMW Z1 was introduced, only available with catalyzed engines. This was a problem in some places like Portugal, where unleaded fuel was still almost non-existent, although European standards required unleaded gasoline to be "available" in every country by 1 October 1989.