human
note 4: property, plant and equipment the following table summarizes the major classes of property, plant and equipment by category as of december 31: 2015 2014 range of remaining useful weighted average useful life utility plant: land and other non-depreciable assets. . . . . . . . . . $141 $137 sources of supply. . . . . . . . . . . . . . . . . . . . . . . . . . 705 681 12 to 127 years 51 years treatment and pumping facilities. . . . . . . . . . . . . . 3070 2969 3 to 101 years 39 years transmission and distribution facilities. . . . . . . . . 8516 7963 9 to 156 years 83 years services, meters and fire hydrants. . . . . . . . . . . . . 3250 3062 8 to 93 years 35 years general structures and equipment. . . . . . . . . . . . . 1227 1096 1 to 154 years 39 years waste treatment, pumping and disposal. . . . . . . . . 313 281 2 to 115 years 46 years waste collection. . . . . . . . . . . . . . . . . . . . . . . . . . . 473 399 5 to 109 years 56 years construction work in progress. . . . . . . . . . . . . . . . 404 303 total utility plant. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18099 16891 nonutility property. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405 378 3 to 50 years 6 years total property, plant and equipment. . . . . . . . . . . . . . . $18504 $17269 property, plant and equipment depreciation expense amounted to $405, $392, and $374 for the years ended december 31, 2015, 2014 and 2013, respectively and was included in depreciation and amortization expense in the accompanying consolidated statements of operations. the provision for depreciation expressed as a percentage of the aggregate average depreciable asset balances was 3.13% (3.13%) for the year ended december 31, 2015 and 3.20% (3.20%) for years december 31, 2014 and 2013. note 5: allowance for uncollectible accounts the following table summarizes the changes in the company 2019s allowances for uncollectible accounts for the years ended december 31:.
|  | 2015 | 2014 | 2013 |
| --------- | --------- | --------- | --------- |
| Balance as of January 1 | $(35) | $(34) | $(27) |
| Amounts charged to expense | (32) | (37) | (27) |
| Amounts written off | 38 | 43 | 24 |
| Recoveries of amounts written off | (10) | (7) | (4) |
| Balance as of December 31 | $(39) | $(35) | $(34) |
.
Please compute the result.
in 2013, as part of the company's noncollectable amounts, how much did those amounts written off represent in relation to the recovered ones?
assistant
6.14286
human
n/a
assistant
31.0
human
n/a
assistant
0.08289