The Class B sector showed continued growth in January, posting a 7.5% year-over-year increase, according to the latest report from Statistical Surveys Inc. Winnebago Industries Inc. was the top-selling manufacturer for the month with 33.9% of the Class B market, followed by Roadtrek Motorhomes Inc. and Thor Industries Inc. . To subscribe to this or other SSI reports, contact Scott Stropkai, national RV sales manager, at 281-9898 ext.