In 'An Hour with Abuelo', one of the main themes is the passage of time. The short time the narrator spends with Abuelo reflects on how time is limited, and within that hour, there are memories, emotions, and family history being shared, which alludes to the broader concept of time's impact on relationships.
It's hard to give an exact figure. The number keeps growing as the creator continues to produce new comics. You could try searching on fan sites or social media groups dedicated to El Goonish Shive for up-to-date information.