This week's review of markets highlights how the collapse in retail sales is evidence of the mounting challenges facing many businesses.   The U.S. consumer, traditionally the key support for the U.S. economy, cannot step in to stop it from tanking.  Growth in industrial production in China is one of the few economic positives and a factor helping to support the share price of mining companies like Rio Tinto.  Income investors will have been pleased by Vodafone's decision to maintain its pay dividend, while, longer term, investors will be wondering if it will be in a position to be sustain the current level of payouts.  This week brings eurozone figures on consumer confidence and UK retail sales figures for April.