January 2014 Sales numbers

Single month sales numbers, year vs. year seem pretty unimportant to me. Too many things can affect sales, like weather, inventories, incentives, general economy, etc. RAM inventories may have been low last year compared to this year, restricting 2013 sales. GM inventories of HDs may be low this January since the new 2015s just went into production. Neither may be a factor, just possibilities, Six month or 12 month rolling sales figures might have more significance.