I'm just curious what's out there in the real world? It seems like most 70% - 80% RDBMS use Oracle as their database engine but I was wondering how many businesses or companies use Microsoft's SQL Server implementation? We avoid all Microsoft products here at my company for several reasons but as I'm learning SQL and becoming more of a DBA, I'm wondering how many companies and or businesses actually use SQL Server over Oracle, PostgreSQL, and MySQL as their main RDBMS?

*Please note I'm not bashing any one vendor / product here but more trying to understand what to expect out there in the real business world.