Why are some comparing this to September of 2014 instead of the last quarter:
Why would you look at year-over-year rather than quarterly growth?
By Investopedia
Growth rates are an important metric for evaluating financial and economic data. Annual growth rates are more commonly cited than quarterly growth rates in equity analysis and stock valuation. Reliance on quarterly growth rates may lead analysts to misinterpret temporary fluctuations as prevailing trends. Quarter-over-quarter changes also fail to capture the effects of seasonality, which are very significant for some companies.
Timing of certain events, the incidence of nonrecurring expenses or simple performance fluctuations are magnified by the smaller sales volumes in a quarter relative to a full year of financial results. This is especially true of smaller companies that may have limited numbers of clients, products or suppliers. Analyzing quarterly growth makes it difficult to isolate trend from circumstance. Many industries experience seasonal demand patterns. Retailers with strong holiday sales are a good example of seasonality. A retailer experiencing revenue decline in the March quarter versus the December quarter is not necessarily reporting poor performance. If the financial results in each of these quarters are superior relative to the year-ago periods, the negative sequential growth rates would be misleading. Though quarterly growth can hold explanatory value and is acceptable from an accounting standpoint, year-over-year growth provides a more complete picture of operating performance trends.
Annual growth rates are also helpful for considering financial performance in the context of other important financial data. Interest rates, return on assets (ROA), return on investments (ROI), return on equity (ROE), dividend yields and other important metrics are expressed on an annual basis. When investors want to assess revenue, net income or cash flow growth rates for a certain company, year-over-year growth rates frame this data in the same context as other important investment statistics. Focusing on annual rates keeps investors in agreement with more commonly used stock market terminology and principles.