[dba-SQLServer] Database market share

The few sites I have found that cite any stats on this use total revenues rather than number of seats. I am more interested in discovering the market share in terms of number of working DBAs and programmers. Oracle claims a 39% share of total DB revenues but that is skewed by the measure of revenues, rather than the number of developer seats. I want to know how many people make their living either as DBAs or programmers in the top 5 databases (Oracle, DB2, MS-SQL, MySQL and <name your poison>). I cannot find stats on this.

Can you provide a link that provides these numbers?

TIA,
Arthur