middle of 1975 when ABBA embarked on a fourteen open-air date tour of Sweden and Finland. Their Stockholm show at the Gröna Lund amusement park had an estimated audience of 19,200. Björn Ulvaeus later said that "If you look at the singles we released straight after Waterloo, we were trying to be more like The Sweet, a semi-glam rock group, which was stupid because we were always a pop group." In late 1974, "So Long" was released as a single in the United Kingdom but it received no airplay from Radio 1 and failed to chart in the UK; the only countries in which it was successful were Austria, Sweden and Germany, reaching the top ten in the first two and number 21 in the latter. In the middle of 1975, ABBA released "I Do, I Do, I Do, I Do, I Do", which again received little airplay on Radio 1, but did manage to climb to number 38 on the UK chart, while making top five in several northern and western European countries, and number one in South Africa. Later that year, the release of their self-titled third studio album ABBA and single "SOS" brought back their chart presence in the UK, where the single hit number six and the album peaked at number 13. "SOS" also became ABBA's second number-one single in Germany, their third in Australia and their first in France, plus reached number two in several other European countries, including Italy. Success was further solidified with "Mamma Mia" reaching number-one in the United Kingdom, Germany and Australia and the top two in a few other western and northern European countries. In the United States, both "I Do, I Do, I Do, I Do, I Do" and "SOS" peaked at number 15 on the Billboard Hot 100 chart, with the latter picking up the BMI Award along the way as one of the most played songs on American radio in 1975. "Mamma Mia", however, stalled at number 32. In Canada, the three songs rose to number 12, nine and 18, respectively. The success of the group in the United States had until that time been limited to single releases. By early 1976, the group already had four Top 30 singles on the US charts, but the album market proved to be tough to crack. The eponymous ABBA album generated three American hits, but it only peaked at