Formula for total entries in a column and for percentage of certain value

Ok, this is going to be somewhat complicated to explain, but I will try my best.

I have a workbook that has 3 sheets in it, Arrests, SFST, and Stats

I need some help calculating the stats.

DUI Investigations needs to calculate a total number entries in column K of the SFST sheet, when a value of "yes" or "no" is entered
DUI Arrests needs reference column K of the SFST sheet, and return a value indicating the number of time "yes" appears in the column
DUI convictions will be the hard one, as it will need to check column G of the Arrest sheet for one of the following values "DUI 1st, DUI 2nd, DUI 3rd, DUI 4th" then cross-reference column I for a value of "conviction" and return the value for how many times the above option and "conviction" occur in the same row.

Then I can input the formulas for the last 2 stats by referencing the above cells.
% Arrests
% Convictions

If it would help, or make it possible, I guess I could split the "Arrest" sheet into "DUI Arrests" and "Other arrests" I have attached a sample workbook

I'm not sure how to remove the original sample workbook, but the 2nd one, "Arrests and SFSTs with content," has some rows of fictitious info

manually giving the answers to us next time would also be very helpful. for now, try this B2:B4 respectively:
=COUNTA(SFST!$K$2:$K$100)
=COUNTIF(SFST!$K$2:$K$100,"yes")
does your entries in column G of the Arrest sheet contain anything other than the 4 "DUI" you mentioned? if no, consider:
=COUNTIFS(Arrests!$G$2:$G$100,"DUI *",Arrests!$I$2:$I$100,"Conviction")
that will count everything that begins with "DUI "
if yes, then maybe:
=SUM(COUNTIFS(Arrests!$G$2:$G$100,{"DUI 1st","DUI 2nd","DUI 3rd","DUI 4th"},Arrests!$I$2:$I$100,"Conviction"))

the last 2 would work only in Excel 2007 & above