Perfective aspect is marked morphologically on the finite verb. Note that a ‘yes’ value does not include periphrastic aspect marking, such as with English <i>have</i>. 

<br><br><b>Reference</b><br>
Dahl, Östen & Velupillai, Viveka. 2008. The Perfect.
In Haspelmath et al. (2008), chapter 68.
Available online at <a href="http://wals.info/feature/68">http://wals.info/feature/68</a href>. 
Accessed on 2008-11-18.