bug on bar?

Hi all,
I've got a strange problem with bar, it seems that xticks are not correctly
draw:

sc.png

···

####################

remi>[16]>years

  Out [16]:[1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006]

remi>[17]>maxis

  Out [17]:[137.25, 124.5, 125.125, 125.375, 176.5, 148.625, 145.875, 150.375]

remi>[18]>bar(years,maxis,align='center')

####################
gives the figure in the sc.png. But if we happend one data in years and in
maxis, xticks are good!
Is it a bug?
PS:mpl version 0.87.7.
--
Lionel Roubeyrie - lroubeyrie@...1068...
LIMAIR
http://www.limair.asso.fr