Question about MTT ROI versus 1 table ROI (Mark Blade)

[nath]

Yeah... my direct buyins range from $11s to $215s (though not often). Plus a smattering of rebuys, usually $11rs but occasionally the $3rs and $5rs (and in one unfortunate incident last night, a $33r).

I just worry I'm headed for a hard crash (and I've been witnessing the cruel side of variance all week). What kind of ROI can a good player expect in MTTs, anyway?