Well it share in the overall market including corporate is miniscule, but interesting to see what is happening at retail (which is really about consumers and small business).
AppleInsider | Apple snags 14 percent of US-based PC retail sales in February
Growth in Apple’s personal computer business continued to outpace the industry average last month, with Macs accounting for a 14 percent unit share and 25 percent dollar share of all US-based PC retail sales, according to market research firm NPD.
As an aside, the market grew 5% on revenues overall and 11% on notebooks, so when you take into account inflation, the PC market at retail is stagnant.