Calculating the ESR of Capacitor
ESR of a capacitor occurs when the impedance of its capacitance and inductance are equal and cancel out leaving only resistance. This occurs at SRF (self resonant frequency). The data sheet you provided only gives impedance at 100 KHz which is unlikely to be the SRF but is as close as you are going to get without measuring it. 100 kHz is a common frequency used for specifying the impedance of electrolytic capacitors as they are commonly used for low frequency filtering.