On the first chart, you're comparing household figures with individuals which isn't fair to the households. It's better to have an amount of money split one way than three ways.
Looks like ~29% of households are dual-income. Meaning we would need to adjust the mean income and contributions for the "US Household" columns by a factor of 1.29. The contributions/income stay the same though.
There's really not a good on-the-fly adjustment one could make for the median measurements. The best approximation I could come up with was 15%, (which is the national median househould income divided by the national median individual income).
I have updated the original post with these adjusted numbers. It looks like my hypothesis was in...
Note: Three data points were removed from the sample due to my subjective opinion that they were fake. Any self-reported IQs of 0 were removed. Any self-reported income of 0 was removed.
*89% of the LW population is between the age of 15 and 34.
**88% of the LW population has an IQ between 125 and 155, with an average IQ of 138.
****Median numbers were adjusted down by a factor of 1.15 to account for the fact that the source data was calculating household median income rather than individual median income.
[1] Internal Revenue Service, Charitable Giving by Households that Itemize Deductions (AGI and Itemized Contributions Summary by Zip, 2012), The Urban Institute, National Center for Charitable Statistics
[2] U.S. Census Bureau, Current Population Survey, 2013 and 2014 Annual Social and Economic Supplements.
[3] Do you have to be smart to be rich? The impact of IQ on wealth, income and financial distress Intelligence, Vol. 35, No. 5. (September 2007), by Jay L. Zagorsky
Update 1: Updated chart 1&2 to account for the fact that the source data was calculating household median income rather than individual income.
Update 2: Reverted Chart 1 back to original because I realized that the purpose was to compare LWers to those in similar income brackets. So in that situation, whether it's a household or an individual is not as relevant. It does penalize households to an extent because they have less money available to donate to charity because they're splitting their money three ways.
Update 3: Updated all charts to include data that is filtered for US only.