area chart dropping some data

[toy]

hey all 
ive got a dataseries here which looks like this

[{"MDetail":"Actual","Amount":2077015154,"Month":"Jan","Monthnum":1,"Year":2011,"d":"2011-1-1"},{"MDetail":"Budget","Amount":1993934548,"Month":"Jan","Monthnum":1,"Year":2011,"d":"2011-1-1"},{"MDetail":"Budget","Amount":2037512363,"Month":"Feb","Monthnum":2,"Year":2011,"d":"2011-2-1"},{"MDetail":"Actual","Amount":2079094248,"Month":"Feb","Monthnum":2,"Year":2011,"d":"2011-2-1"},{"MDetail":"Budget","Amount":2060363670,"Month":"Mar","Monthnum":3,"Year":2011,"d":"2011-3-1"},{"MDetail":"Actual","Amount":2081175424,"Month":"Mar","Monthnum":3,"Year":2011,"d":"2011-3-1"},{"MDetail":"Budget","Amount":2020760922,"Month":"Apr","Monthnum":4,"Year":2011,"d":"2011-4-1"},{"MDetail":"Actual","Amount":2083258683,"Month":"Apr","Monthnum":4,"Year":2011,"d":"2011-4-1"},{"MDetail":"Budget","Amount":2043637146,"Month":"May","Monthnum":5,"Year":2011,"d":"2011-5-1"},{"MDetail":"Actual","Amount":2085344027,"Month":"May","Monthnum":5,"Year":2011,"d":"2011-5-1"},{"MDetail":"Budget","Amount":2024808514,"Month":"Jun","Monthnum":6,"Year":2011,"d":"2011-6-1"},{"MDetail":"Actual","Amount":2087431458,"Month":"Jun","Monthnum":6,"Year":2011,"d":"2011-6-1"},{"MDetail":"Budget","Amount":2026835350,"Month":"Jul","Monthnum":7,"Year":2011,"d":"2011-7-1"},{"MDetail":"Actual","Amount":2089520979,"Month":"Jul","Monthnum":7,"Year":2011,"d":"2011-7-1"},{"MDetail":"Budget","Amount":2070696466,"Month":"Aug","Monthnum":8,"Year":2011,"d":"2011-8-1"},{"MDetail":"Actual","Amount":2091612592,"Month":"Aug","Monthnum":8,"Year":2011,"d":"2011-8-1"},{"MDetail":"Actual","Amount":2093706298,"Month":"Sep","Monthnum":9,"Year":2011,"d":"2011-9-1"},{"MDetail":"Budget","Amount":2114643361,"Month":"Sep","Monthnum":9,"Year":2011,"d":"2011-9-1"},{"MDetail":"Actual","Amount":2095802100,"Month":"Oct","Monthnum":10,"Year":2011,"d":"2011-10-1"},{"MDetail":"Budget","Amount":2137718142,"Month":"Oct","Monthnum":10,"Year":2011,"d":"2011-10-1"},{"MDetail":"Actual","Amount":2097900000,"Month":"Nov","Monthnum":11,"Year":2011,"d":"2011-11-1"},{"MDetail":"Budget","Amount":2118879000,"Month":"Nov","Monthnum":11,"Year":2011,"d":"2011-11-1"},{"MDetail":"Actual","Amount":2100000000,"Month":"Dec","Monthnum":12,"Year":2011,"d":"2011-12-1"},{"MDetail":"Budget","Amount":2079000000,"Month":"Dec","Monthnum":12,"Year":2011,"d":"2011-12-1"}]

the chart works great
EXCEPT: feb, oct and nov drop down to 0
and dec doesnt even show up

which is odd since all the other months look great
and the data looks consistent

any ideas?

you can see the chart here:
www.the-agora.com