Here are the readings for the week, month, year and two years, plus the entire set of CO2 ppm readings at MLO since 1958 as of February 26, 2014
The rate of annual increase between December 2013 from 2012 ranged between 2.3-2.5 ppm.
While a focus on the CO2 record at Mauna Loa is helpful, in reality many locations are reporting above 400 ppm this winter. For example, the Barrow, AK CO2 readings reached almost 405 ppm in January, 2014.
The following image is the average global CO2 in the atmosphere as of February 26, 2014, 0-12 hours UTC as imaged by the METOP A IASI satellite instrument. The yellows are atmospheric levels above 410 ppm for the entire atmospheric column - not just the surface
In individual atmospheric layers, the actual readings in these areas may be much higher, but the METOP reporting has restricted the highest readings to 420 ppm.
Although the entire mean is 396 ppm, it is only a matter of time before we cross 400 ppm level globally.
Barrow, AK CO2: http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts
METOP IASI at NOAA: http://www.osdpd.noaa.gov/IASI/html/index.html