With the increased popularity of the knitted suit, knitting mills included men's and women's swimming apparel in their more prosaic lines of underwear and sweaters. Many companies advertised the new product, steadily increasing their range until the inevitable occurred. In 1921 a national advertising campaign for swimming suits was initiated by Jantzen, a hitherto obscure knitting mill whose production had been limited to sweaters, woolen hosiery, and jackets for Chinese workmen. Capitalizing on the growing interest in swimming, Jantzen prominently advertised swimming suits instead of bathing dresses. The retail stores selling these suits advertised locally, but national advertising became the domain of the manufacturers, educating the public to associate certain positive qualities with their names. To the delight of the swim suit industry, swimming was more than a passing vogue. In 1934, a National Recreation Association study on the use of leisure time found that among ninety-four free-time activities swimming was second only to movies in popularity.[66] Although the number of swimmers was increasing, competition caused the swim suit industry to take a new approach. Manufacturers attempted to increase the volume of sales through advertising by emphasizing style. In 1927 one company advertised a national appeal to woman's vanity by declaring that beach _uniforms_ were out and that beach _styles_ were in. [66] _The Leisure Hours of 5,000 People; a Report of a Study of Leisure Time Activities and Desires_ (New York, National Recreation Assoc., 1934). It was a general characteristic of the 1930s that swimming suits covered less of the bather. The attached trunks of the swimming suit no longer extended down the leg but it survived unseen beneath the vestigial remains of a skirt. The diminishing coverage of the swim suit was also related to a changing attitude toward sun exposure. For years women had protected their delicate skin to prevent any unladylike, healthy appearance. The barrier against a lady having a tan deteriorated as women became accepted into athletic activities. By 1930, women eagerly sought a sun tan. Not only were there lotions to help the neophyte sun-worshiper acquire a rich even tan, but creams were available for the impatient who wished an instant tan. In line with this trend, swim suit manufacturers and sellers promoted and sold low sun-back or California styles, halter necks, and cut-out sections that exposed various portions of the midriff. The favorite suit, however, was the form-fitting maillot of wool jersey with no skirt.