lumens of sun compared to my 1000 Watt HPS bulb???

just wondering how many lumens are put off by the average 1000 Watt HPS bulb, and also how many lumens are put off by the sun? basically i have plants indoors under a 1000 Watt HPS and i have several plants outdoors in the sun and i wanna know what the difference is between the amount of lumens my plants are getting??

i'm pretty sure at the ground in summer a good average is 10,000 lumens/ft2

most 1000 watt hps are around 150,000 lumens

the caveat? - you lose about 1/4 of your lumens every foot you move away from the light
a light meter is essential in placing a larger grow to ensure proper distribution