U.S. Senate race poll numbers, visualized

I've put together a graphic of the polls published so far in the race for Tom Coburn's U.S. Senate seat.

Here are the numbers per candidate in each poll:

	Lankford	Shannon	Brogdon	Other	Undecided
1/30-2/2	54	18		1	27
2/10-2/12	47	17		3	33
3/16-3/17	37	28	7	3	23
4/23-4/29	30.8	32	3.5	1.3	32.5
4/27-4/29	36	34	6	3	21
April-May average	33.4	33	4.75	2.15	26.75