Are substitutes having an impact more than ever before?

After Nottingham Forest's substitutes combined to stun Liverpool at Anfield at the weekend, are we seeing a rise in the impact of players from off the bench in the Premier League?

Are substitutes having an impact more than ever before?
After Nottingham Forest's substitutes combined to stun Liverpool at Anfield at the weekend, are we seeing a rise in the impact of players from off the bench in the Premier League?