Hi TF, You guessed the correct answer. It's cumulative withdrawals, not monthly. Yes, the house project and the huge 2000 cap gain tax (and estimated taxes) ballooned that section of the chart.
(this is only the third time since 1986 that my cash reserves have run dry!)
Since 1990, I've withdrawn almost as much money as the current residual value of the equities remaining! Once those $$$ are withdrawn they don't change in value. If they were still there as cash, they'd at least earn something. The only way I could think of to equate my account to someone's that doesn't use it for living expenses was to keep track of the amounts I remove from the system each month and then accumulate the total. It is getting to be a rather large anchor on the graph. I'll have to think about whether it continues to makes sense to present it this way.
I should have a bit of relief now as one child is out of college and waiting a year before grad school. The next one isn't due in college for another three years. The house project is complete at this point, so expenses should moderate. We all know there's not much to be paid for Capital Gains in recent times!!!