What qualifies as good sales?

[Slimebeast]

HappySqurriel said:

There is no universal barrier that would be considered "Good Sales" that would cover most games; as an example 1 Million units sold would (probably) be considered very successful for Boom Blox, and the same sales would make Grand Theft Auto 4 one of the biggest flops of all time. I do think that the following schedule is (probably) a pretty good starting point though:

	DS	Wii/PS2/PSP	Xbox 360/PS3
Low Budget	60,000 to 125,000	125,000 to 250,000	250,000 to 500,000
Average	125,000 to 250,000	250,000 to 500,000	500,000 to 1,000,000
Big Budget	250,000 to 500,000	500,000 to 1,000,000	1,000,000 to 2,000,000

What's the source of these numbers?