From the excellent
http://www.swindon-town-fc.co.uk/Lee Peacock (Subsitute appearences in brackets)
'08/'09.......20 (+11) 3 goals
'07/'08...... 40 (+1) 6 goals
'06/'07......42 (+2) 10 goals
Barry Corr
'08/'09........3 (+11) 2 goals
'07/'08........9 (+11) 5 goals
'06/'07........8 (+0) 3 goals
Not sure that's quite the correlation you wanted.