Default

Storage space usage: 0 blocks used (out of 1 total) 
Storage space usage: <meter value=0>0 blocks used (out of 1 total)</meter>

with value

Storage space usage: 1 blocks used (out of 1 total) 
Storage space usage: <meter value=1>1 blocks used (out of 1 total)</meter>

with max

Storage space usage: 2 blocks used (out of 10 total) 
Storage space usage: <meter value=2 max=10>2 blocks used (out of 10 total)</meter>